diff --git a/cpu/mpc5xxx/start.S b/cpu/mpc5xxx/start.S
index 37448ac..216c1c8 100644
--- a/cpu/mpc5xxx/start.S
+++ b/cpu/mpc5xxx/start.S
@@ -103,7 +103,7 @@
 boot_warm:
 	mfmsr	r5			/* save msr contents		*/
 
-#if defined(CFG_DEFAULT_MBAR)
+#if defined(CFG_DEFAULT_MBAR) && !defined(CFG_RAMBOOT)
 	lis	r3, CFG_MBAR@h
 	ori	r3, r3, CFG_MBAR@l
 #if defined(CONFIG_MPC5200)