diff --git a/TRDOS/TR_HDD_4.ASZ b/TRDOS/TR_HDD_4.ASZ
index 8624673..0149b0d 100644
--- a/TRDOS/TR_HDD_4.ASZ
+++ b/TRDOS/TR_HDD_4.ASZ
@@ -181,8 +181,8 @@ CHOOSE_HDD:
 	PUSH	BC
 	LD	BC,(ZX_VARS.OPER_DISK - 1)
 	; LD	B,A
-	; XOR A
-	LD C,BIOS.HDD_TO_DRV
+	; XOR	A
+	LD	C,BIOS.HDD_TO_DRV
 	CALL	EXP_FNS
 	POP	AF
 	RET