diff --git a/boot/floppy.asm b/boot/floppy.asm
index d8468f7..c72fa21 100644
--- a/boot/floppy.asm
+++ b/boot/floppy.asm
@@ -168,7 +168,7 @@ main:
   mov ds, ax
   mov es, ax
   mov ss, ax
-  mov sp, ax
+  xor sp, sp
   mov [fdc.drv], dl ; save drive number in fdc
   sti