diff --git a/Source/HBIOS/sd.asm b/Source/HBIOS/sd.asm
index 327189b6..993fb175 100644
--- a/Source/HBIOS/sd.asm
+++ b/Source/HBIOS/sd.asm
@@ -2141,7 +2141,7 @@ SD_DESELECT:
 #ENDIF
 ;
 #IF (SDMODE == SDMODE_FZ80)
-	;;;CALL	SD_WAITBSY
+	CALL	SD_WAITBSY
 #ENDIF
 ;
 	LD	A,(SD_OPRVAL)
@@ -2277,7 +2277,7 @@ SD_PUT1:
 #ENDIF
 ;
 #IF (SDMODE == SDMODE_FZ80)
-	;;;CALL	SD_WAITBSY		; WAIT FOR PENDING ACTIVITY
+	CALL	SD_WAITBSY		; WAIT FOR PENDING ACTIVITY
 	OUT	(SD_DATA),A		; POST THE VALUE
 	OUT	(SD_ACTION),A		; INITIATE THE WRITE
 	;;;CALL	PC_SPACE		; *DEBUG*
@@ -2388,7 +2388,7 @@ SD_GET1:
 #ENDIF
 ;
 #IF (SDMODE == SDMODE_FZ80)
-	;;;CALL	SD_WAITBSY		; WAIT FOR PENDING ACTIVITY
+	CALL	SD_WAITBSY		; WAIT FOR PENDING ACTIVITY
 	IN	A,(SD_ACTION)		; INITIATE READ
 	;;;CALL	SD_WAITBSY		; WAIT FOR DONE
 	IN	A,(SD_DATA)		; GET THE VALUE
diff --git a/Source/ver.inc b/Source/ver.inc
index 54a84855..1f6eca4f 100644
--- a/Source/ver.inc
+++ b/Source/ver.inc
@@ -2,7 +2,7 @@
 #DEFINE	RMN	6
 #DEFINE	RUP	0
 #DEFINE	RTP	0
-#DEFINE BIOSVER	"3.6.0-dev.20"
+#DEFINE BIOSVER	"3.6.0-dev.21"
 #define rmj	RMJ
 #define rmn	RMN
 #define rup	RUP
diff --git a/Source/ver.lib b/Source/ver.lib
index 98689530..08ba2678 100644
--- a/Source/ver.lib
+++ b/Source/ver.lib
@@ -3,5 +3,5 @@ rmn	equ	6
 rup	equ	0
 rtp	equ	0
 biosver	macro
-	db	"3.6.0-dev.20"
+	db	"3.6.0-dev.21"
 	endm