diff --git a/boot/fat.asm b/boot/fat.asm
index 1e253dd..7abafa5 100644
--- a/boot/fat.asm
+++ b/boot/fat.asm
@@ -119,7 +119,7 @@ resetbuf:	; DS = ES
 		xor di, di
 		; AX,CX = 0
 		xor ax, ax
-		xor cx, cx
+		xor dx, dx
 		ret
 
 main:		mov bp, params