diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index ac780d4..e6d8be5 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -54,11 +54,11 @@
 # Workaround for local bus unaligned access problems
 # on MPC512x and MPC5200
 ifdef CONFIG_MPC512X
-$(obj)/ppcstring.o: AFLAGS += -Dmemcpy=__memcpy
+AFLAGS_ppcstring.o += -Dmemcpy=__memcpy
 obj-y += memcpy_mpc5200.o
 endif
 ifdef CONFIG_MPC5200
-$(obj)/ppcstring.o: AFLAGS += -Dmemcpy=__memcpy
+AFLAGS_ppcstring.o += -Dmemcpy=__memcpy
 obj-y += memcpy_mpc5200.o
 endif
 endif