diff --git a/arch/m68k/kernel/uboot.c b/arch/m68k/kernel/uboot.c
index b29c3b241e1b..107082877064 100644
--- a/arch/m68k/kernel/uboot.c
+++ b/arch/m68k/kernel/uboot.c
@@ -102,5 +102,5 @@ __init void process_uboot_commandline(char *commandp, int size)
 	}
 
 	parse_uboot_commandline(commandp, len);
-	commandp[size - 1] = 0;
+	commandp[len - 1] = 0;
 }