From e4cdc3d1679daaffce46430425d26a2f76608598 Mon Sep 17 00:00:00 2001
From: Wayne Warthen <wwarthen@gmail.com>
Date: Sun, 10 Jan 2021 10:18:30 -0800
Subject: [PATCH] More SD Card Compatibility Changes

Based on a logic analyzer trace from Andy Cooper, it appears that some SD cards want the unused CRC byte of the command packet to be 0xFF instead of the 0x00 filler I was using.  Changed to put 0xFF in the CRC byte when unused.
---
 Source/HBIOS/sd.asm | 2 ++
 Source/ver.inc      | 2 +-
 Source/ver.lib      | 2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Source/HBIOS/sd.asm b/Source/HBIOS/sd.asm
index 16ebed91..b8df9f64 100644
--- a/Source/HBIOS/sd.asm
+++ b/Source/HBIOS/sd.asm
@@ -1320,6 +1320,8 @@ SD_INITCMD1:
 	INC	HL			; POINT TO NEXT BYTE
 	LD	(HL),A			; CLEAR IT
 	DJNZ	SD_INITCMD1		; LOOP TILL DONE
+	DEC	A			; $FF TO ACCUM
+	LD	(SD_CMDCRC),A		; PUT $FF IN CRC POSITION
 	RET
 ;
 ; EXECUTE APP COMMAND
diff --git a/Source/ver.inc b/Source/ver.inc
index 3df45cbb..29bea73d 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,4 +2,4 @@
 #DEFINE	RMN	1
 #DEFINE	RUP	1
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.1.1-pre.26"
+#DEFINE BIOSVER	"3.1.1-pre.27"
diff --git a/Source/ver.lib b/Source/ver.lib
index 5cb9993b..b773165e 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	1
 rup	equ	1
 rtp	equ	0
 biosver	macro
-	db	"3.1.1-pre.26"
+	db	"3.1.1-pre.27"
 	endm