diff --git a/cpu/74xx_7xx/start.S b/cpu/74xx_7xx/start.S
index 07bbe01de9..b5484e3745 100644
--- a/cpu/74xx_7xx/start.S
+++ b/cpu/74xx_7xx/start.S
@@ -857,9 +857,9 @@ lock_ram_in_cache:
 	 */
 	lis	r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@h
 	ori	r3, r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@l
-	li	r2, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
+	li	r4, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
 		     (CONFIG_SYS_INIT_RAM_ADDR & 31) + 31) / 32
-	mtctr	r2
+	mtctr	r4
 1:
 	dcbz	r0, r3
 	addi	r3, r3, 32
@@ -878,9 +878,9 @@ unlock_ram_in_cache:
 	/* invalidate the INIT_RAM section */
 	lis	r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@h
 	ori	r3, r3, (CONFIG_SYS_INIT_RAM_ADDR & ~31)@l
-	li	r2, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
+	li	r4, ((CONFIG_SYS_INIT_RAM_END & ~31) + \
 		     (CONFIG_SYS_INIT_RAM_ADDR & 31) + 31) / 32
-	mtctr	r2
+	mtctr	r4
 1:	icbi	r0, r3
 	addi	r3, r3, 32
 	bdnz	1b