diff --git a/lib/Makefile b/lib/Makefile
index e44e045..f83f6e8 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -48,6 +48,7 @@
 COBJS-y += ldiv.o
 COBJS-$(CONFIG_MD5) += md5.o
 COBJS-y += net_utils.o
+COBJS-$(CONFIG_PHYSMEM) += physmem.o
 COBJS-y += qsort.o
 COBJS-$(CONFIG_SHA1) += sha1.o
 COBJS-$(CONFIG_SHA256) += sha256.o