diff --git a/src/soc/intel/xeon_sp/cpx/chip.c b/src/soc/intel/xeon_sp/cpx/chip.c
index 3daff13..b7752b2 100644
--- a/src/soc/intel/xeon_sp/cpx/chip.c
+++ b/src/soc/intel/xeon_sp/cpx/chip.c
@@ -11,8 +11,10 @@
 #include <soc/chip_common.h>
 #include <soc/cpu.h>
 #include <soc/ramstage.h>
+#include <soc/p2sb.h>
 #include <soc/soc_util.h>
 #include <soc/util.h>
+#include <soc/pci_devs.h>
 
 /* UPD parameters to be initialized before SiliconInit */
 void platform_fsp_silicon_init_params_cb(FSPS_UPD *silupd)
@@ -63,6 +65,8 @@
 
 static void chip_final(void *data)
 {
+	/* Lock SBI */
+	pci_or_config32(PCH_DEV_P2SB, P2SBC, SBILOCK);
 	p2sb_hide();
 
 	set_bios_init_completion();