diff --git a/src/mainboard/apple/macbook21/Makefile.inc b/src/mainboard/apple/macbook21/Makefile.inc
index 5819897..115d7e9 100644
--- a/src/mainboard/apple/macbook21/Makefile.inc
+++ b/src/mainboard/apple/macbook21/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += gpio.c
 bootblock-y += early_init.c
 romstage-y += early_init.c
diff --git a/src/mainboard/apple/macbookair4_2/Makefile.inc b/src/mainboard/apple/macbookair4_2/Makefile.inc
index 665a95f..36e4258 100644
--- a/src/mainboard/apple/macbookair4_2/Makefile.inc
+++ b/src/mainboard/apple/macbookair4_2/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-y += gnvs.c
diff --git a/src/mainboard/asrock/b85m_pro4/Makefile.inc b/src/mainboard/asrock/b85m_pro4/Makefile.inc
index d9a8d18..5464360 100644
--- a/src/mainboard/asrock/b85m_pro4/Makefile.inc
+++ b/src/mainboard/asrock/b85m_pro4/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += gpio.c
 
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads
diff --git a/src/mainboard/asrock/g41c-gs/Makefile.inc b/src/mainboard/asrock/g41c-gs/Makefile.inc
index ab352cb..bb906a6 100644
--- a/src/mainboard/asrock/g41c-gs/Makefile.inc
+++ b/src/mainboard/asrock/g41c-gs/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 
diff --git a/src/mainboard/asus/p2b/Makefile.inc b/src/mainboard/asus/p2b/Makefile.inc
index eb48944..6e1fb3f 100644
--- a/src/mainboard/asus/p2b/Makefile.inc
+++ b/src/mainboard/asus/p2b/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 romstage-$(CONFIG_BOARD_ASUS_P3B_F) += variants/$(VARIANT_DIR)/romstage.c
 
diff --git a/src/mainboard/asus/p5gc-mx/Makefile.inc b/src/mainboard/asus/p5gc-mx/Makefile.inc
index a34f3f3..95250e2 100644
--- a/src/mainboard/asus/p5gc-mx/Makefile.inc
+++ b/src/mainboard/asus/p5gc-mx/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 bootblock-y += early_init.c
diff --git a/src/mainboard/asus/p5qpl-am/Makefile.inc b/src/mainboard/asus/p5qpl-am/Makefile.inc
index ab352cb..bb906a6 100644
--- a/src/mainboard/asus/p5qpl-am/Makefile.inc
+++ b/src/mainboard/asus/p5qpl-am/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 
diff --git a/src/mainboard/biostar/th61-itx/Makefile.inc b/src/mainboard/biostar/th61-itx/Makefile.inc
index 549a84f..33b55d2 100644
--- a/src/mainboard/biostar/th61-itx/Makefile.inc
+++ b/src/mainboard/biostar/th61-itx/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/bytedance/bd_egs/Makefile.inc b/src/mainboard/bytedance/bd_egs/Makefile.inc
index e6e739e..be3ae0c 100644
--- a/src/mainboard/bytedance/bd_egs/Makefile.inc
+++ b/src/mainboard/bytedance/bd_egs/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c gpio.c
 romstage-y += romstage.c
 ramstage-y += ramstage.c gpio.c
diff --git a/src/mainboard/clevo/cml-u/Makefile.inc b/src/mainboard/clevo/cml-u/Makefile.inc
index e71e87a..babadf5 100644
--- a/src/mainboard/clevo/cml-u/Makefile.inc
+++ b/src/mainboard/clevo/cml-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/$(VARIANT_DIR)/acpi
 
diff --git a/src/mainboard/clevo/cml-u/variants/l140cu/Makefile.inc b/src/mainboard/clevo/cml-u/variants/l140cu/Makefile.inc
index 09089b4..7f547fb 100644
--- a/src/mainboard/clevo/cml-u/variants/l140cu/Makefile.inc
+++ b/src/mainboard/clevo/cml-u/variants/l140cu/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 SPD_SOURCES  = samsung-K4AAG165WA-BCTD
diff --git a/src/mainboard/clevo/tgl-u/Makefile.inc b/src/mainboard/clevo/tgl-u/Makefile.inc
index 0d57383..ae492df 100644
--- a/src/mainboard/clevo/tgl-u/Makefile.inc
+++ b/src/mainboard/clevo/tgl-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/variants/$(VARIANT_DIR)/acpi
 
diff --git a/src/mainboard/clevo/tgl-u/variants/l140mu/Makefile.inc b/src/mainboard/clevo/tgl-u/variants/l140mu/Makefile.inc
index 10cb4fb..361cbcd 100644
--- a/src/mainboard/clevo/tgl-u/variants/l140mu/Makefile.inc
+++ b/src/mainboard/clevo/tgl-u/variants/l140mu/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 SPD_SOURCES  = samsung-M471A1G44AB0-CWE
diff --git a/src/mainboard/compulab/intense_pc/Makefile.inc b/src/mainboard/compulab/intense_pc/Makefile.inc
index e402ffa..e4b6fbf 100644
--- a/src/mainboard/compulab/intense_pc/Makefile.inc
+++ b/src/mainboard/compulab/intense_pc/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/emulation/qemu-i440fx/Makefile.inc b/src/mainboard/emulation/qemu-i440fx/Makefile.inc
index 7bd1c02..7d6041b 100644
--- a/src/mainboard/emulation/qemu-i440fx/Makefile.inc
+++ b/src/mainboard/emulation/qemu-i440fx/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += memmap.c
 
 postcar-y += memmap.c
diff --git a/src/mainboard/emulation/qemu-q35/Makefile.inc b/src/mainboard/emulation/qemu-q35/Makefile.inc
index dc4e794..f4a89be 100644
--- a/src/mainboard/emulation/qemu-q35/Makefile.inc
+++ b/src/mainboard/emulation/qemu-q35/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-y += memmap.c
 
diff --git a/src/mainboard/foxconn/d41s/Makefile.inc b/src/mainboard/foxconn/d41s/Makefile.inc
index 057b5bf..6e0b914 100644
--- a/src/mainboard/foxconn/d41s/Makefile.inc
+++ b/src/mainboard/foxconn/d41s/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += early_init.c
 bootblock-y += early_init.c
 ramstage-y += cstates.c
diff --git a/src/mainboard/foxconn/g41s-k/Makefile.inc b/src/mainboard/foxconn/g41s-k/Makefile.inc
index 161c623..b4e5dcc 100644
--- a/src/mainboard/foxconn/g41s-k/Makefile.inc
+++ b/src/mainboard/foxconn/g41s-k/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/gigabyte/ga-945gcm-s2l/Makefile.inc b/src/mainboard/gigabyte/ga-945gcm-s2l/Makefile.inc
index a34f3f3..95250e2 100644
--- a/src/mainboard/gigabyte/ga-945gcm-s2l/Makefile.inc
+++ b/src/mainboard/gigabyte/ga-945gcm-s2l/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 bootblock-y += early_init.c
diff --git a/src/mainboard/gigabyte/ga-g41m-es2l/Makefile.inc b/src/mainboard/gigabyte/ga-g41m-es2l/Makefile.inc
index 4100476..de8c514 100644
--- a/src/mainboard/gigabyte/ga-g41m-es2l/Makefile.inc
+++ b/src/mainboard/gigabyte/ga-g41m-es2l/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/gigabyte/ga-h61m-series/Makefile.inc b/src/mainboard/gigabyte/ga-h61m-series/Makefile.inc
index 9916927..6b13e84 100644
--- a/src/mainboard/gigabyte/ga-h61m-series/Makefile.inc
+++ b/src/mainboard/gigabyte/ga-h61m-series/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += variants/$(VARIANT_DIR)/gpio.c
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 
diff --git a/src/mainboard/google/asurada/Makefile.inc b/src/mainboard/google/asurada/Makefile.inc
index 84600b6..63073bc 100644
--- a/src/mainboard/google/asurada/Makefile.inc
+++ b/src/mainboard/google/asurada/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 subdirs-y += sdram_params/
 
 bootblock-y += memlayout.ld
diff --git a/src/mainboard/google/asurada/sdram_params/Makefile.inc b/src/mainboard/google/asurada/sdram_params/Makefile.inc
index 20df2ba..2ce2442 100644
--- a/src/mainboard/google/asurada/sdram_params/Makefile.inc
+++ b/src/mainboard/google/asurada/sdram_params/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 sdram-params :=
 
 # Generic parameters
diff --git a/src/mainboard/google/brya/Makefile.inc b/src/mainboard/google/brya/Makefile.inc
index b98c3ee..8c7e42d 100644
--- a/src/mainboard/google/brya/Makefile.inc
+++ b/src/mainboard/google/brya/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 
 verstage-$(CONFIG_CHROMEOS) += chromeos.c
diff --git a/src/mainboard/google/brya/variants/aurash/Makefile.inc b/src/mainboard/google/brya/variants/aurash/Makefile.inc
index b799b4d..35cff38 100644
--- a/src/mainboard/google/brya/variants/aurash/Makefile.inc
+++ b/src/mainboard/google/brya/variants/aurash/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/baseboard/brask/Makefile.inc b/src/mainboard/google/brya/variants/baseboard/brask/Makefile.inc
index 8121d7e..96950d7 100644
--- a/src/mainboard/google/brya/variants/baseboard/brask/Makefile.inc
+++ b/src/mainboard/google/brya/variants/baseboard/brask/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/google/brya/variants/baseboard/brya/Makefile.inc b/src/mainboard/google/brya/variants/baseboard/brya/Makefile.inc
index f2efc1d..3a66958 100644
--- a/src/mainboard/google/brya/variants/baseboard/brya/Makefile.inc
+++ b/src/mainboard/google/brya/variants/baseboard/brya/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/google/brya/variants/baseboard/hades/Makefile.inc b/src/mainboard/google/brya/variants/baseboard/hades/Makefile.inc
index 7c75e20..47123cd 100644
--- a/src/mainboard/google/brya/variants/baseboard/hades/Makefile.inc
+++ b/src/mainboard/google/brya/variants/baseboard/hades/Makefile.inc
@@ -1,2 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += memory.c
 ramstage-y += ramstage.c
diff --git a/src/mainboard/google/brya/variants/baseboard/nissa/Makefile.inc b/src/mainboard/google/brya/variants/baseboard/nissa/Makefile.inc
index 53aaa41..3743228 100644
--- a/src/mainboard/google/brya/variants/baseboard/nissa/Makefile.inc
+++ b/src/mainboard/google/brya/variants/baseboard/nissa/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/google/brya/variants/brya0/Makefile.inc b/src/mainboard/google/brya/variants/brya0/Makefile.inc
index 52d0398..4a7ff71 100644
--- a/src/mainboard/google/brya/variants/brya0/Makefile.inc
+++ b/src/mainboard/google/brya/variants/brya0/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
diff --git a/src/mainboard/google/brya/variants/crota/Makefile.inc b/src/mainboard/google/brya/variants/crota/Makefile.inc
index f9d5990..ebdc2e3 100644
--- a/src/mainboard/google/brya/variants/crota/Makefile.inc
+++ b/src/mainboard/google/brya/variants/crota/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/gaelin/Makefile.inc b/src/mainboard/google/brya/variants/gaelin/Makefile.inc
index 7d1f886..2cddd11 100644
--- a/src/mainboard/google/brya/variants/gaelin/Makefile.inc
+++ b/src/mainboard/google/brya/variants/gaelin/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/gothrax/Makefile.inc b/src/mainboard/google/brya/variants/gothrax/Makefile.inc
index 6c29346..a49954c 100644
--- a/src/mainboard/google/brya/variants/gothrax/Makefile.inc
+++ b/src/mainboard/google/brya/variants/gothrax/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/hades/Makefile.inc b/src/mainboard/google/brya/variants/hades/Makefile.inc
index 81d298a..e272dc2 100644
--- a/src/mainboard/google/brya/variants/hades/Makefile.inc
+++ b/src/mainboard/google/brya/variants/hades/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/moli/Makefile.inc b/src/mainboard/google/brya/variants/moli/Makefile.inc
index b799b4d..35cff38 100644
--- a/src/mainboard/google/brya/variants/moli/Makefile.inc
+++ b/src/mainboard/google/brya/variants/moli/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/skolas/Makefile.inc b/src/mainboard/google/brya/variants/skolas/Makefile.inc
index 52d0398..4a7ff71 100644
--- a/src/mainboard/google/brya/variants/skolas/Makefile.inc
+++ b/src/mainboard/google/brya/variants/skolas/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
diff --git a/src/mainboard/google/brya/variants/skolas4es/Makefile.inc b/src/mainboard/google/brya/variants/skolas4es/Makefile.inc
index 52d0398..4a7ff71 100644
--- a/src/mainboard/google/brya/variants/skolas4es/Makefile.inc
+++ b/src/mainboard/google/brya/variants/skolas4es/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
diff --git a/src/mainboard/google/brya/variants/taeko/Makefile.inc b/src/mainboard/google/brya/variants/taeko/Makefile.inc
index 396e5be..47f0432 100644
--- a/src/mainboard/google/brya/variants/taeko/Makefile.inc
+++ b/src/mainboard/google/brya/variants/taeko/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/taeko4es/Makefile.inc b/src/mainboard/google/brya/variants/taeko4es/Makefile.inc
index 396e5be..47f0432 100644
--- a/src/mainboard/google/brya/variants/taeko4es/Makefile.inc
+++ b/src/mainboard/google/brya/variants/taeko4es/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/brya/variants/taniks/Makefile.inc b/src/mainboard/google/brya/variants/taniks/Makefile.inc
index 3ee0dc9..61a70ec 100644
--- a/src/mainboard/google/brya/variants/taniks/Makefile.inc
+++ b/src/mainboard/google/brya/variants/taniks/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/cherry/Makefile.inc b/src/mainboard/google/cherry/Makefile.inc
index 4edbd38..5fe1339 100644
--- a/src/mainboard/google/cherry/Makefile.inc
+++ b/src/mainboard/google/cherry/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += memlayout.ld
 bootblock-y += bootblock.c
 bootblock-y += chromeos.c
diff --git a/src/mainboard/google/corsola/Makefile.inc b/src/mainboard/google/corsola/Makefile.inc
index da6775a..dce226f 100644
--- a/src/mainboard/google/corsola/Makefile.inc
+++ b/src/mainboard/google/corsola/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += memlayout.ld
 bootblock-y += bootblock.c
 bootblock-y += chromeos.c
diff --git a/src/mainboard/google/dedede/Makefile.inc b/src/mainboard/google/dedede/Makefile.inc
index ec1c065..fdc2630 100644
--- a/src/mainboard/google/dedede/Makefile.inc
+++ b/src/mainboard/google/dedede/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-$(CONFIG_CHROMEOS) += chromeos.c
 
diff --git a/src/mainboard/google/dedede/variants/baseboard/Makefile.inc b/src/mainboard/google/dedede/variants/baseboard/Makefile.inc
index 2c3f2f6..a58371a 100644
--- a/src/mainboard/google/dedede/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/dedede/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/fizz/variants/baseboard/Makefile.inc b/src/mainboard/google/fizz/variants/baseboard/Makefile.inc
index 0ad298b..476f28f 100644
--- a/src/mainboard/google/fizz/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/fizz/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/fizz/variants/endeavour/Makefile.inc b/src/mainboard/google/fizz/variants/endeavour/Makefile.inc
index ded8a35..6ff6456 100644
--- a/src/mainboard/google/fizz/variants/endeavour/Makefile.inc
+++ b/src/mainboard/google/fizz/variants/endeavour/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/fizz/variants/karma/Makefile.inc b/src/mainboard/google/fizz/variants/karma/Makefile.inc
index ec115e4..8d74101 100644
--- a/src/mainboard/google/fizz/variants/karma/Makefile.inc
+++ b/src/mainboard/google/fizz/variants/karma/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/geralt/Makefile.inc b/src/mainboard/google/geralt/Makefile.inc
index d2fda23..9a35496 100644
--- a/src/mainboard/google/geralt/Makefile.inc
+++ b/src/mainboard/google/geralt/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += memlayout.ld
 bootblock-y += bootblock.c
 bootblock-y += chromeos.c
diff --git a/src/mainboard/google/guybrush/variants/baseboard/Makefile.inc b/src/mainboard/google/guybrush/variants/baseboard/Makefile.inc
index cfd3faa..74d030d 100644
--- a/src/mainboard/google/guybrush/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/guybrush/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 bootblock-y += helpers.c
 
diff --git a/src/mainboard/google/kukui/Makefile.inc b/src/mainboard/google/kukui/Makefile.inc
index 968ee19..7b0298d 100644
--- a/src/mainboard/google/kukui/Makefile.inc
+++ b/src/mainboard/google/kukui/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 subdirs-y += sdram_params/
 subdirs-y += panel_params/
 
diff --git a/src/mainboard/google/kukui/sdram_params/Makefile.inc b/src/mainboard/google/kukui/sdram_params/Makefile.inc
index cb8f427..e7fc110 100644
--- a/src/mainboard/google/kukui/sdram_params/Makefile.inc
+++ b/src/mainboard/google/kukui/sdram_params/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 sdram-params :=
 sdram-params += sdram-lpddr4x-K4UBE3D4AA-MGCR-4GB
 sdram-params += sdram-lpddr4x-H9HCNNNCPMALHR-4GB
diff --git a/src/mainboard/google/mistral/Makefile.inc b/src/mainboard/google/mistral/Makefile.inc
index 48faadf..1cbaa8b 100644
--- a/src/mainboard/google/mistral/Makefile.inc
+++ b/src/mainboard/google/mistral/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 bootblock-y += chromeos.c
 bootblock-y += reset.c
diff --git a/src/mainboard/google/myst/variants/baseboard/Makefile.inc b/src/mainboard/google/myst/variants/baseboard/Makefile.inc
index 9e9ec0d..d5e133a 100644
--- a/src/mainboard/google/myst/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/myst/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-$(CONFIG_FW_CONFIG) += fw_config.c
diff --git a/src/mainboard/google/octopus/Makefile.inc b/src/mainboard/google/octopus/Makefile.inc
index dd49610..accb463 100644
--- a/src/mainboard/google/octopus/Makefile.inc
+++ b/src/mainboard/google/octopus/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-y += ec.c
 
diff --git a/src/mainboard/google/octopus/variants/ampton/Makefile.inc b/src/mainboard/google/octopus/variants/ampton/Makefile.inc
index dc1c1fe..c717243 100644
--- a/src/mainboard/google/octopus/variants/ampton/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/ampton/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/baseboard/Makefile.inc b/src/mainboard/google/octopus/variants/baseboard/Makefile.inc
index 06f125c..ace6dee 100644
--- a/src/mainboard/google/octopus/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/google/octopus/variants/bloog/Makefile.inc b/src/mainboard/google/octopus/variants/bloog/Makefile.inc
index 5228e70..86a53c0 100644
--- a/src/mainboard/google/octopus/variants/bloog/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/bloog/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/bobba/Makefile.inc b/src/mainboard/google/octopus/variants/bobba/Makefile.inc
index a854b66..17f22e5 100644
--- a/src/mainboard/google/octopus/variants/bobba/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/bobba/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/casta/Makefile.inc b/src/mainboard/google/octopus/variants/casta/Makefile.inc
index ba865e9..3c26f0a 100644
--- a/src/mainboard/google/octopus/variants/casta/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/casta/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/dood/Makefile.inc b/src/mainboard/google/octopus/variants/dood/Makefile.inc
index a854b66..17f22e5 100644
--- a/src/mainboard/google/octopus/variants/dood/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/dood/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/fleex/Makefile.inc b/src/mainboard/google/octopus/variants/fleex/Makefile.inc
index 9a649bda..ac62f6b 100644
--- a/src/mainboard/google/octopus/variants/fleex/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/fleex/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/foob/Makefile.inc b/src/mainboard/google/octopus/variants/foob/Makefile.inc
index 86a10df..a2f85b0 100644
--- a/src/mainboard/google/octopus/variants/foob/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/foob/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/garg/Makefile.inc b/src/mainboard/google/octopus/variants/garg/Makefile.inc
index 16211b7..6d41a6d 100644
--- a/src/mainboard/google/octopus/variants/garg/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/garg/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/lick/Makefile.inc b/src/mainboard/google/octopus/variants/lick/Makefile.inc
index 9fb63f5..9f8b781 100644
--- a/src/mainboard/google/octopus/variants/lick/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/lick/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/meep/Makefile.inc b/src/mainboard/google/octopus/variants/meep/Makefile.inc
index 7277888..4526e12 100644
--- a/src/mainboard/google/octopus/variants/meep/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/meep/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/phaser/Makefile.inc b/src/mainboard/google/octopus/variants/phaser/Makefile.inc
index 1b171c5..eda39ac 100644
--- a/src/mainboard/google/octopus/variants/phaser/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/phaser/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/octopus/variants/yorp/Makefile.inc b/src/mainboard/google/octopus/variants/yorp/Makefile.inc
index 0ec849f..f1a61afd 100644
--- a/src/mainboard/google/octopus/variants/yorp/Makefile.inc
+++ b/src/mainboard/google/octopus/variants/yorp/Makefile.inc
@@ -1,2 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
diff --git a/src/mainboard/google/poppy/spd/Makefile.inc b/src/mainboard/google/poppy/spd/Makefile.inc
index 997352c..83fbfc5 100644
--- a/src/mainboard/google/poppy/spd/Makefile.inc
+++ b/src/mainboard/google/poppy/spd/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SEC_SPD_BIN = $(obj)/sec-spd.bin
 
diff --git a/src/mainboard/google/poppy/variants/atlas/Makefile.inc b/src/mainboard/google/poppy/variants/atlas/Makefile.inc
index 397ef68..dc9062c 100644
--- a/src/mainboard/google/poppy/variants/atlas/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/atlas/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SPD_SOURCES  = empty                            # 0b0000
 SPD_SOURCES += samsung_dimm_K4E8E324EB-EGCF     # 0b0001
diff --git a/src/mainboard/google/poppy/variants/baseboard/Makefile.inc b/src/mainboard/google/poppy/variants/baseboard/Makefile.inc
index 41669f2..0d70ca2 100644
--- a/src/mainboard/google/poppy/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/google/poppy/variants/nami/Makefile.inc b/src/mainboard/google/poppy/variants/nami/Makefile.inc
index 7c1e480..7d9e81e 100644
--- a/src/mainboard/google/poppy/variants/nami/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/nami/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 # IMPORTANT!! When a new memory SPD is added here, please ensure that ddp_bitmap
 # is correctly updated in memory.c to indicate if memory id is using DDP.
diff --git a/src/mainboard/google/poppy/variants/nautilus/Makefile.inc b/src/mainboard/google/poppy/variants/nautilus/Makefile.inc
index 3a36b83b..80e43fd 100644
--- a/src/mainboard/google/poppy/variants/nautilus/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/nautilus/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SPD_SOURCES  = samsung_dimm_K4E8E324EB-EGCF     # 0b0000
 SPD_SOURCES += samsung_dimm_K4E6E304EB-EGCF     # 0b0001
diff --git a/src/mainboard/google/poppy/variants/nocturne/Makefile.inc b/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
index 371655a..f5544f6 100644
--- a/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/nocturne/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SPD_SOURCES  = empty				# 0b0000
 SPD_SOURCES += samsung_dimm_K4E8E324EB-EGCF	# 0b0001  4GB
diff --git a/src/mainboard/google/poppy/variants/poppy/Makefile.inc b/src/mainboard/google/poppy/variants/poppy/Makefile.inc
index ecd1451..15d803a 100644
--- a/src/mainboard/google/poppy/variants/poppy/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/poppy/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SPD_SOURCES = empty				# 0b0000
 SPD_SOURCES += micron_dimm_MT52L256M64D2PP-107	# 0b0001
diff --git a/src/mainboard/google/poppy/variants/rammus/Makefile.inc b/src/mainboard/google/poppy/variants/rammus/Makefile.inc
index 2baeb52..6bee4f8 100644
--- a/src/mainboard/google/poppy/variants/rammus/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/rammus/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 SPD_SOURCES  = micron_dimm_MT52L512M32D2PF-093	# 0b0000
 SPD_SOURCES += samsung_dimm_K4E8E324EB-EGCF     # 0b0001
 SPD_SOURCES += micron_dimm_MT52L256M32D1PF-093	# 0b0010
diff --git a/src/mainboard/google/poppy/variants/soraka/Makefile.inc b/src/mainboard/google/poppy/variants/soraka/Makefile.inc
index 9b14da6..ec06f40 100644
--- a/src/mainboard/google/poppy/variants/soraka/Makefile.inc
+++ b/src/mainboard/google/poppy/variants/soraka/Makefile.inc
@@ -1,3 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 SPD_SOURCES = empty				# 0b0000
 SPD_SOURCES += micron_dimm_MT52L256M64D2PP-107	# 0b0001
diff --git a/src/mainboard/google/reef/Makefile.inc b/src/mainboard/google/reef/Makefile.inc
index dd49610..accb463 100644
--- a/src/mainboard/google/reef/Makefile.inc
+++ b/src/mainboard/google/reef/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-y += ec.c
 
diff --git a/src/mainboard/google/reef/variants/baseboard/Makefile.inc b/src/mainboard/google/reef/variants/baseboard/Makefile.inc
index 1484261..8ee85af 100644
--- a/src/mainboard/google/reef/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/reef/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/reef/variants/coral/Makefile.inc b/src/mainboard/google/reef/variants/coral/Makefile.inc
index 440ec9c..9ec0276 100644
--- a/src/mainboard/google/reef/variants/coral/Makefile.inc
+++ b/src/mainboard/google/reef/variants/coral/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += mainboard.c
diff --git a/src/mainboard/google/reef/variants/pyro/Makefile.inc b/src/mainboard/google/reef/variants/pyro/Makefile.inc
index fd45b94..be05cd4 100644
--- a/src/mainboard/google/reef/variants/pyro/Makefile.inc
+++ b/src/mainboard/google/reef/variants/pyro/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += memory.c
diff --git a/src/mainboard/google/reef/variants/snappy/Makefile.inc b/src/mainboard/google/reef/variants/snappy/Makefile.inc
index f3c87b2..ffdfd17 100644
--- a/src/mainboard/google/reef/variants/snappy/Makefile.inc
+++ b/src/mainboard/google/reef/variants/snappy/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += mainboard.c
diff --git a/src/mainboard/google/rex/Makefile.inc b/src/mainboard/google/rex/Makefile.inc
index cd6be13..8c60c59 100644
--- a/src/mainboard/google/rex/Makefile.inc
+++ b/src/mainboard/google/rex/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 
 verstage-$(CONFIG_CHROMEOS) += chromeos.c
diff --git a/src/mainboard/google/rex/variants/baseboard/ovis/Makefile.inc b/src/mainboard/google/rex/variants/baseboard/ovis/Makefile.inc
index bb3620a..2bf1925 100644
--- a/src/mainboard/google/rex/variants/baseboard/ovis/Makefile.inc
+++ b/src/mainboard/google/rex/variants/baseboard/ovis/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += memory.c
 
 ramstage-y += ramstage.c
diff --git a/src/mainboard/google/rex/variants/baseboard/rex/Makefile.inc b/src/mainboard/google/rex/variants/baseboard/rex/Makefile.inc
index bb3620a..2bf1925 100644
--- a/src/mainboard/google/rex/variants/baseboard/rex/Makefile.inc
+++ b/src/mainboard/google/rex/variants/baseboard/rex/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += memory.c
 
 ramstage-y += ramstage.c
diff --git a/src/mainboard/google/rex/variants/karis/Makefile.inc b/src/mainboard/google/rex/variants/karis/Makefile.inc
index 6c29346..a49954c 100644
--- a/src/mainboard/google/rex/variants/karis/Makefile.inc
+++ b/src/mainboard/google/rex/variants/karis/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/rex/variants/ovis/Makefile.inc b/src/mainboard/google/rex/variants/ovis/Makefile.inc
index b785122..4c33dad 100644
--- a/src/mainboard/google/rex/variants/ovis/Makefile.inc
+++ b/src/mainboard/google/rex/variants/ovis/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 romstage-y += memory.c
diff --git a/src/mainboard/google/rex/variants/rex0/Makefile.inc b/src/mainboard/google/rex/variants/rex0/Makefile.inc
index cdbf407..0f9a28b 100644
--- a/src/mainboard/google/rex/variants/rex0/Makefile.inc
+++ b/src/mainboard/google/rex/variants/rex0/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-y += gpio.c
diff --git a/src/mainboard/google/rex/variants/screebo/Makefile.inc b/src/mainboard/google/rex/variants/screebo/Makefile.inc
index 192041b..8bea0ff 100644
--- a/src/mainboard/google/rex/variants/screebo/Makefile.inc
+++ b/src/mainboard/google/rex/variants/screebo/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/google/skyrim/variants/baseboard/Makefile.inc b/src/mainboard/google/skyrim/variants/baseboard/Makefile.inc
index 7828cf1..0f7cc89 100644
--- a/src/mainboard/google/skyrim/variants/baseboard/Makefile.inc
+++ b/src/mainboard/google/skyrim/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += gpio.c
diff --git a/src/mainboard/hp/compaq_8200_elite_sff/Makefile.inc b/src/mainboard/hp/compaq_8200_elite_sff/Makefile.inc
index f0b34f9..2099428 100644
--- a/src/mainboard/hp/compaq_8200_elite_sff/Makefile.inc
+++ b/src/mainboard/hp/compaq_8200_elite_sff/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads
diff --git a/src/mainboard/hp/compaq_elite_8300_usdt/Makefile.inc b/src/mainboard/hp/compaq_elite_8300_usdt/Makefile.inc
index 18391d8..fb492d3 100644
--- a/src/mainboard/hp/compaq_elite_8300_usdt/Makefile.inc
+++ b/src/mainboard/hp/compaq_elite_8300_usdt/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += early_init.c
 bootblock-y += gpio.c
 romstage-y += early_init.c
diff --git a/src/mainboard/hp/folio_9480m/Makefile.inc b/src/mainboard/hp/folio_9480m/Makefile.inc
index ebe01ae..6f4727a 100644
--- a/src/mainboard/hp/folio_9480m/Makefile.inc
+++ b/src/mainboard/hp/folio_9480m/Makefile.inc
@@ -1,2 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += gpio.c
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads
diff --git a/src/mainboard/hp/z220_series/Makefile.inc b/src/mainboard/hp/z220_series/Makefile.inc
index 00426a8..69ef088 100644
--- a/src/mainboard/hp/z220_series/Makefile.inc
+++ b/src/mainboard/hp/z220_series/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += variants/$(VARIANT_DIR)/gpio.c
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads
diff --git a/src/mainboard/ibase/mb899/Makefile.inc b/src/mainboard/ibase/mb899/Makefile.inc
index 992c373..ad8a084 100644
--- a/src/mainboard/ibase/mb899/Makefile.inc
+++ b/src/mainboard/ibase/mb899/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += superio_hwm.c
 ramstage-y += cstates.c
 romstage-y += gpio.c
diff --git a/src/mainboard/ibm/sbp1/Makefile.inc b/src/mainboard/ibm/sbp1/Makefile.inc
index 0688aa1..4c7a7be 100644
--- a/src/mainboard/ibm/sbp1/Makefile.inc
+++ b/src/mainboard/ibm/sbp1/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 romstage-y += romstage.c
 ramstage-y += ramstage.c
diff --git a/src/mainboard/intel/apollolake_rvp/Makefile.inc b/src/mainboard/intel/apollolake_rvp/Makefile.inc
index 8501868..d604d02 100644
--- a/src/mainboard/intel/apollolake_rvp/Makefile.inc
+++ b/src/mainboard/intel/apollolake_rvp/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
diff --git a/src/mainboard/intel/archercity_crb/Makefile.inc b/src/mainboard/intel/archercity_crb/Makefile.inc
index 0688aa1..4c7a7be 100644
--- a/src/mainboard/intel/archercity_crb/Makefile.inc
+++ b/src/mainboard/intel/archercity_crb/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 romstage-y += romstage.c
 ramstage-y += ramstage.c
diff --git a/src/mainboard/intel/cedarisland_crb/Makefile.inc b/src/mainboard/intel/cedarisland_crb/Makefile.inc
index 3da456e..bf162bb 100644
--- a/src/mainboard/intel/cedarisland_crb/Makefile.inc
+++ b/src/mainboard/intel/cedarisland_crb/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 romstage-y += romstage.c
 ramstage-y += ramstage.c
diff --git a/src/mainboard/intel/coffeelake_rvp/variants/baseboard/Makefile.inc b/src/mainboard/intel/coffeelake_rvp/variants/baseboard/Makefile.inc
index 0ad298b..476f28f 100644
--- a/src/mainboard/intel/coffeelake_rvp/variants/baseboard/Makefile.inc
+++ b/src/mainboard/intel/coffeelake_rvp/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/intel/d510mo/Makefile.inc b/src/mainboard/intel/d510mo/Makefile.inc
index f87689b..e546b9d 100644
--- a/src/mainboard/intel/d510mo/Makefile.inc
+++ b/src/mainboard/intel/d510mo/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += early_init.c
 romstage-y += early_init.c
 ramstage-y += cstates.c
diff --git a/src/mainboard/intel/d945gclf/Makefile.inc b/src/mainboard/intel/d945gclf/Makefile.inc
index a34f3f3..95250e2 100644
--- a/src/mainboard/intel/d945gclf/Makefile.inc
+++ b/src/mainboard/intel/d945gclf/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 bootblock-y += early_init.c
diff --git a/src/mainboard/intel/dcp847ske/Makefile.inc b/src/mainboard/intel/dcp847ske/Makefile.inc
index 08aa2dd..f8c155e 100644
--- a/src/mainboard/intel/dcp847ske/Makefile.inc
+++ b/src/mainboard/intel/dcp847ske/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += early_southbridge.c
 romstage-y += early_southbridge.c
 bootblock-y += gpio.c
diff --git a/src/mainboard/intel/dg41wv/Makefile.inc b/src/mainboard/intel/dg41wv/Makefile.inc
index 4100476..de8c514 100644
--- a/src/mainboard/intel/dg41wv/Makefile.inc
+++ b/src/mainboard/intel/dg41wv/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/intel/dq67sw/Makefile.inc b/src/mainboard/intel/dq67sw/Makefile.inc
index 18391d8..fb492d3 100644
--- a/src/mainboard/intel/dq67sw/Makefile.inc
+++ b/src/mainboard/intel/dq67sw/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += early_init.c
 bootblock-y += gpio.c
 romstage-y += early_init.c
diff --git a/src/mainboard/intel/glkrvp/Makefile.inc b/src/mainboard/intel/glkrvp/Makefile.inc
index 72247b2..965a6f8 100644
--- a/src/mainboard/intel/glkrvp/Makefile.inc
+++ b/src/mainboard/intel/glkrvp/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-y += ec.c
 
diff --git a/src/mainboard/intel/glkrvp/variants/baseboard/Makefile.inc b/src/mainboard/intel/glkrvp/variants/baseboard/Makefile.inc
index d2d344c..b0d35e8 100644
--- a/src/mainboard/intel/glkrvp/variants/baseboard/Makefile.inc
+++ b/src/mainboard/intel/glkrvp/variants/baseboard/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += boardid.c
diff --git a/src/mainboard/intel/leafhill/Makefile.inc b/src/mainboard/intel/leafhill/Makefile.inc
index c3077e7..ec5b262 100644
--- a/src/mainboard/intel/leafhill/Makefile.inc
+++ b/src/mainboard/intel/leafhill/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 
 romstage-y += romstage.c
diff --git a/src/mainboard/intel/minnow3/Makefile.inc b/src/mainboard/intel/minnow3/Makefile.inc
index 3e9bf68..a90af29 100644
--- a/src/mainboard/intel/minnow3/Makefile.inc
+++ b/src/mainboard/intel/minnow3/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 bootblock-y += gpio.c
 
diff --git a/src/mainboard/inventec/transformers/Makefile.inc b/src/mainboard/inventec/transformers/Makefile.inc
index 7619419..ecb6ef2 100644
--- a/src/mainboard/inventec/transformers/Makefile.inc
+++ b/src/mainboard/inventec/transformers/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 romstage-y += romstage.c
 romstage-$(CONFIG_IPMI_KCS_ROMSTAGE) += ipmi.c
diff --git a/src/mainboard/kontron/986lcd-m/Makefile.inc b/src/mainboard/kontron/986lcd-m/Makefile.inc
index a34f3f3..95250e2 100644
--- a/src/mainboard/kontron/986lcd-m/Makefile.inc
+++ b/src/mainboard/kontron/986lcd-m/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 bootblock-y += early_init.c
diff --git a/src/mainboard/kontron/ktqm77/Makefile.inc b/src/mainboard/kontron/ktqm77/Makefile.inc
index e402ffa..e4b6fbf 100644
--- a/src/mainboard/kontron/ktqm77/Makefile.inc
+++ b/src/mainboard/kontron/ktqm77/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/kontron/mal10/Makefile.inc b/src/mainboard/kontron/mal10/Makefile.inc
index 7fbab00..2a21e03 100644
--- a/src/mainboard/kontron/mal10/Makefile.inc
+++ b/src/mainboard/kontron/mal10/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 ramstage-y += ramstage.c
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += variants/$(VARIANT_DIR)/gma-mainboard.ads
diff --git a/src/mainboard/kontron/mal10/carriers/t10-tni/Makefile.inc b/src/mainboard/kontron/mal10/carriers/t10-tni/Makefile.inc
index c291d45..5d3bcc4 100644
--- a/src/mainboard/kontron/mal10/carriers/t10-tni/Makefile.inc
+++ b/src/mainboard/kontron/mal10/carriers/t10-tni/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += gpio.c
diff --git a/src/mainboard/kontron/mal10/variants/mal10/Makefile.inc b/src/mainboard/kontron/mal10/variants/mal10/Makefile.inc
index 4b48156..f0aa6b1 100644
--- a/src/mainboard/kontron/mal10/variants/mal10/Makefile.inc
+++ b/src/mainboard/kontron/mal10/variants/mal10/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
diff --git a/src/mainboard/lenovo/haswell/Makefile.inc b/src/mainboard/lenovo/haswell/Makefile.inc
index d1300f8..3861ea1 100644
--- a/src/mainboard/lenovo/haswell/Makefile.inc
+++ b/src/mainboard/lenovo/haswell/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 romstage-y += variants/$(VARIANT_DIR)/romstage.c
 
diff --git a/src/mainboard/lenovo/haswell/variants/t440p/Makefile.inc b/src/mainboard/lenovo/haswell/variants/t440p/Makefile.inc
index f3c87b2..ffdfd17 100644
--- a/src/mainboard/lenovo/haswell/variants/t440p/Makefile.inc
+++ b/src/mainboard/lenovo/haswell/variants/t440p/Makefile.inc
@@ -1 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += mainboard.c
diff --git a/src/mainboard/lenovo/s230u/Makefile.inc b/src/mainboard/lenovo/s230u/Makefile.inc
index 31bb642..073d8b2 100644
--- a/src/mainboard/lenovo/s230u/Makefile.inc
+++ b/src/mainboard/lenovo/s230u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 ramstage-y += ec.c
diff --git a/src/mainboard/lenovo/t430/Makefile.inc b/src/mainboard/lenovo/t430/Makefile.inc
index e402ffa..e4b6fbf 100644
--- a/src/mainboard/lenovo/t430/Makefile.inc
+++ b/src/mainboard/lenovo/t430/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/lenovo/thinkcentre_a58/Makefile.inc b/src/mainboard/lenovo/thinkcentre_a58/Makefile.inc
index 4100476..de8c514 100644
--- a/src/mainboard/lenovo/thinkcentre_a58/Makefile.inc
+++ b/src/mainboard/lenovo/thinkcentre_a58/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 ramstage-y += cstates.c
 romstage-y += gpio.c
 
diff --git a/src/mainboard/msi/h81m-p33/Makefile.inc b/src/mainboard/msi/h81m-p33/Makefile.inc
index d9a8d18..5464360 100644
--- a/src/mainboard/msi/h81m-p33/Makefile.inc
+++ b/src/mainboard/msi/h81m-p33/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 romstage-y += gpio.c
 
 ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads
diff --git a/src/mainboard/msi/ms7707/Makefile.inc b/src/mainboard/msi/ms7707/Makefile.inc
index 2fa05da..10bd6bc 100644
--- a/src/mainboard/msi/ms7707/Makefile.inc
+++ b/src/mainboard/msi/ms7707/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 romstage-y += gpio.c
 bootblock-y += early_init.c
diff --git a/src/mainboard/siemens/mc_apl1/Makefile.inc b/src/mainboard/siemens/mc_apl1/Makefile.inc
index 124e380..e179201 100644
--- a/src/mainboard/siemens/mc_apl1/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 
 # The inclusion of romstage.c is not necessary here.
diff --git a/src/mainboard/siemens/mc_apl1/variants/baseboard/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/baseboard/Makefile.inc
index e553581..be05cd4 100644
--- a/src/mainboard/siemens/mc_apl1/variants/baseboard/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/baseboard/Makefile.inc
@@ -1,2 +1,3 @@
+## SPDX-License-Identifier: GPL-2.0-only
 
 romstage-y += memory.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl1/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl1/Makefile.inc
index 3629aca..dff9c79 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl1/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl1/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl2/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl2/Makefile.inc
index 152b46e..f2a034c 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl2/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl2/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl3/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl3/Makefile.inc
index 152b46e..f2a034c 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl3/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl3/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl4/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl4/Makefile.inc
index e26339c..621ffd1 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl4/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl4/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl5/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/Makefile.inc
index 3629aca..dff9c79 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl5/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl6/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl6/Makefile.inc
index 152b46e..f2a034c 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl6/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl6/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
diff --git a/src/mainboard/siemens/mc_apl1/variants/mc_apl7/Makefile.inc b/src/mainboard/siemens/mc_apl1/variants/mc_apl7/Makefile.inc
index ecab3cc..af6f16c 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl7/Makefile.inc
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl7/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += gpio.c
 
 romstage-y += memory.c
diff --git a/src/mainboard/supermicro/x9scl/Makefile.inc b/src/mainboard/supermicro/x9scl/Makefile.inc
index 3465dfe..c83c7f3 100644
--- a/src/mainboard/supermicro/x9scl/Makefile.inc
+++ b/src/mainboard/supermicro/x9scl/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += early_init.c
 bootblock-y += gpio.c
 romstage-y += early_init.c
diff --git a/src/mainboard/system76/addw1/Makefile.inc b/src/mainboard/system76/addw1/Makefile.inc
index fedde68..0942459 100644
--- a/src/mainboard/system76/addw1/Makefile.inc
+++ b/src/mainboard/system76/addw1/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/adl/Makefile.inc b/src/mainboard/system76/adl/Makefile.inc
index 9dea9f3..c5334f1 100644
--- a/src/mainboard/system76/adl/Makefile.inc
+++ b/src/mainboard/system76/adl/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/bonw14/Makefile.inc b/src/mainboard/system76/bonw14/Makefile.inc
index a866021..2efcac5 100644
--- a/src/mainboard/system76/bonw14/Makefile.inc
+++ b/src/mainboard/system76/bonw14/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/cml-u/Makefile.inc b/src/mainboard/system76/cml-u/Makefile.inc
index 51ad543..921112c 100644
--- a/src/mainboard/system76/cml-u/Makefile.inc
+++ b/src/mainboard/system76/cml-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/gaze15/Makefile.inc b/src/mainboard/system76/gaze15/Makefile.inc
index 32a4099..72f1366 100644
--- a/src/mainboard/system76/gaze15/Makefile.inc
+++ b/src/mainboard/system76/gaze15/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/kbl-u/Makefile.inc b/src/mainboard/system76/kbl-u/Makefile.inc
index d749e41..bf3828d 100644
--- a/src/mainboard/system76/kbl-u/Makefile.inc
+++ b/src/mainboard/system76/kbl-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/oryp5/Makefile.inc b/src/mainboard/system76/oryp5/Makefile.inc
index 7c0701e..e52ccca 100644
--- a/src/mainboard/system76/oryp5/Makefile.inc
+++ b/src/mainboard/system76/oryp5/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/oryp6/Makefile.inc b/src/mainboard/system76/oryp6/Makefile.inc
index 2267eb6..ab8e965 100644
--- a/src/mainboard/system76/oryp6/Makefile.inc
+++ b/src/mainboard/system76/oryp6/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/system76/tgl-u/Makefile.inc b/src/mainboard/system76/tgl-u/Makefile.inc
index ca14835..28ada02 100644
--- a/src/mainboard/system76/tgl-u/Makefile.inc
+++ b/src/mainboard/system76/tgl-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 ifeq ($(CONFIG_BOARD_SYSTEM76_GALP5),y)
diff --git a/src/mainboard/system76/whl-u/Makefile.inc b/src/mainboard/system76/whl-u/Makefile.inc
index d749e41..bf3828d 100644
--- a/src/mainboard/system76/whl-u/Makefile.inc
+++ b/src/mainboard/system76/whl-u/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
 bootblock-y += bootblock.c
diff --git a/src/mainboard/up/squared/Makefile.inc b/src/mainboard/up/squared/Makefile.inc
index af2508e..68ddfca 100644
--- a/src/mainboard/up/squared/Makefile.inc
+++ b/src/mainboard/up/squared/Makefile.inc
@@ -1,3 +1,5 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
 bootblock-y += bootblock.c
 
 romstage-y += romstage.c