diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index b207ffe..432e24e 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -40,5 +40,6 @@
 smm-y += memcpy.c cbfs.c memset.c memcmp.c
 smm-$(CONFIG_CONSOLE_SERIAL8250) += uart8250.c
 smm-$(CONFIG_CONSOLE_SERIAL8250MEM) += uart8250mem.c
+smm-$(CONFIG_USBDEBUG) += usbdebug.c
 
 $(obj)/lib/version.ramstage.o : $(obj)/build.h