diff --git a/Doc/RomWBW Applications.pdf b/Doc/RomWBW Applications.pdf
index 32c6ccf2..0cce82cc 100644
Binary files a/Doc/RomWBW Applications.pdf and b/Doc/RomWBW Applications.pdf differ
diff --git a/Doc/RomWBW Architecture.pdf b/Doc/RomWBW Architecture.pdf
index bb2f238e..e75d8164 100644
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diff --git a/Doc/RomWBW Disk Catalog.pdf b/Doc/RomWBW Disk Catalog.pdf
index 73b19980..4a7bcc18 100644
Binary files a/Doc/RomWBW Disk Catalog.pdf and b/Doc/RomWBW Disk Catalog.pdf differ
diff --git a/Doc/RomWBW Getting Started.pdf b/Doc/RomWBW Getting Started.pdf
index 4e161bbf..31c94949 100644
Binary files a/Doc/RomWBW Getting Started.pdf and b/Doc/RomWBW Getting Started.pdf differ
diff --git a/Source/Apps/Tune/hbios.inc b/Source/Apps/Tune/hbios.inc
index f2442f78..2f5d177d 100644
--- a/Source/Apps/Tune/hbios.inc
+++ b/Source/Apps/Tune/hbios.inc
@@ -9,7 +9,8 @@ BF_SYSGET	.EQU	$F8		; HBIOS: SYSGET function
 
 BF_SND		.EQU	$50
 BF_SNDRESET	.EQU	BF_SND + 0	; RESET SOUND SYSTEM
-BF_SNDVOL	.EQU	BF_SND + 1	; REQUEST SOUND VOL - D IS CHANNEL, E CONTAINS VOLUME (255 MAX, 0 SILENT) - SCALED AS REQUIRED BY DRIVER (EG: MAPS TO JUST 4 BIT RESOLUTION FOR SN76489)
-BF_SNDPRD	.EQU	BF_SND + 2	; REQUEST SOUND PERIOD - D IS CHANNEL, HL CONTAINS PERIOD (0 LOWEST NOTE) - SCALED BY DRIVER (EG: MAPS TO JUST 10 BITS FOR SN76489 )
+BF_SNDVOL	.EQU	BF_SND + 1	; REQUEST SOUND VOL - L CONTAINS VOLUME (255 MAX, 0 SILENT) - SCALED AS REQUIRED BY DRIVER (EG: MAPS TO JUST 4 BIT RESOLUTION FOR SN76489)
+BF_SNDPRD	.EQU	BF_SND + 2	; REQUEST SOUND PERIOD - HL CONTAINS DRIVER SPECIFIC VALUE
+BF_SNDNOTE	.EQU	BF_SND + 3	; REQUEST NOTE - L CONTAINS NOTE - EACH VALUE IS QUARTER NOTE
 BF_SNDPLAY	.EQU	BF_SND + 4	; INITIATE THE REQUESTED SOUND COMMAND
-BF_SNDQUERY	.EQU	BF_SND + 5	; D IS CHANNEL, E IS SUBCOMMAND
+BF_SNDQUERY	.EQU	BF_SND + 5	; E IS SUBFUNCTION
diff --git a/Source/Doc/Architecture.md b/Source/Doc/Architecture.md
index f7523d5e..7ead4371 100644
--- a/Source/Doc/Architecture.md
+++ b/Source/Doc/Architecture.md
@@ -1374,7 +1374,7 @@ chip provides.
 | _Entry Parameters_
 |       B: 0x52
 |       C: Audio Device Unit ID
-|       HL: Period (0000=lowest note, FFFF=highest note)
+|       HL: Period
 
 |      _Returned Values_
 |           A: Status (0=OK, else error)
@@ -1383,7 +1383,9 @@ This function sets the sound chip period parameter.  The period will
 be applied when the next SNDPLAY function is invoked.
 
 The period value is a driver specific value.  To play standardized
-notes, use the SNDNOTE function.
+notes, use the SNDNOTE function.  A higher value will generate a lower
+note.  The maximum value that can be used is driver specific. If value
+supplied is beyond driver capabilities, register A will be set to $FF.
 
 ### Function 0x53 -- Sound Note (SNDNOTE)
 
diff --git a/Source/HBIOS/sd.asm b/Source/HBIOS/sd.asm
index ef187081..1fefcfa7 100644
--- a/Source/HBIOS/sd.asm
+++ b/Source/HBIOS/sd.asm
@@ -866,7 +866,7 @@ SD_INITCARD1:
 	; MAKE SURE WE FINISH SENDING
 #IF ((SDMODE == SDMODE_CSIO) | (SDMODE == SDMODE_MK4) | (SDMODE == SDMODE_SC))
 	CALL	SD_WAITTX		; WAIT FOR TE TO CLEAR
-	CALL	DLY4			; WAIT A BIT MORE FOR FINAL BIT
+	CALL	DLY32			; WAIT A BIT MORE FOR FINAL BIT
 #ENDIF
 ;
 	; PUT CARD IN IDLE STATE
@@ -1025,7 +1025,7 @@ SD_INITCARD5:
 	; PER SPEC, THE CARD SHOULD NOW BE ABLE TO HANDLE FULL SPEED OPERATION
 	; SO, FOR CSIO OPERATION, WE SET CSIO TO MAXIMUM SPEED
 	CALL	SD_WAITTX		; MAKE SURE WE ARE DONE SENDING
-	CALL	DLY4			; WAIT A BIT MORE FOR FINAL BIT
+	CALL	DLY32			; WAIT A BIT MORE FOR FINAL BIT
 	XOR	A			; ZERO MEANS MAX SPEED
 	OUT	(Z180_CNTR),A		; NOW SET CSIO PORT
 #ENDIF
@@ -1674,12 +1674,10 @@ SD_DESELECT:
 	; FINISH SENDING AFTER TE IS CLEARED.  THE DELAY BELOW WILL
 	; DO THIS FOR THE SLOWEST POSSIBLE SEND RATE WHICH IS
 	; CLK / 1320, SO DELAY AT LEAST 1320 T-STATES
-	;CALL	DLY64			; DELAY FOR FINAL BIT
 ;
-	; IN PRACTICE, IT LOOKS LIKE THIS WORST CASE SCENARIO NEVER
-	; OCCURS.  FOR NOW, USE A SMALL DELAY WHICH SEEMS TO BE MORE
-	; THAN ADEQUATE BASED ON LOGIC ANALYZER TRACES.
-	CALL	DLY4			; DELAY FOR FINAL BIT
+	; IN PRACTICE, A SMALLER DELAY IS FINE BASED ON LOGIC ANALYZER
+	; TRACES.
+	CALL	DLY32			; DELAY FOR FINAL BIT
 #ENDIF
 ;
 	LD	A,(SD_OPRVAL)