diff --git a/src/arch/i386/loader.S b/src/arch/i386/loader.S
index 83ab011..e30ad56 100644
--- a/src/arch/i386/loader.S
+++ b/src/arch/i386/loader.S
@@ -53,6 +53,7 @@ _start:
 	mov	$stack_top, %esp
 	xor	%ebp, %ebp
 
+	/* save %eax to detect multiboot */
 	push	%eax
 
 	/* reset EFLAGS */