diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c
index ffb9c5c9d7486efb0a61fff5a73c5995aa9b32e0..212004ec787de87e788b94a00f5b15bfc055b585 100644
--- a/arch/x86/boot/compressed/string.c
+++ b/arch/x86/boot/compressed/string.c
@@ -1,5 +1,7 @@
 #include "misc.h"
 
+/* Avoid intereference from any defines in string_32.h */
+#undef memcmp
 int memcmp(const void *s1, const void *s2, size_t len)
 {
 	u8 diff;