diff --git a/asm_routines/dos33_routines.s b/asm_routines/dos33_routines.s
index 8cc0ab70..160bdcc8 100644
--- a/asm_routines/dos33_routines.s
+++ b/asm_routines/dos33_routines.s
@@ -72,6 +72,7 @@ filename_pad_spaces:
 	cpy	#30			; fill 30 bytes
 	bne	filename_pad_spaces
 
+filename_pad_done:
 
 	ldy	#8			; filename ptr offset = 8
 	lda	#<filename
@@ -83,15 +84,39 @@ filename_pad_spaces:
 	ldx	#1	 		; open existing file
 
 	jsr	dos33_open		; open file
+	bcs	error_open
 
 	jsr	dos33_read		; read buffer
+	bcc	now_close
+					; got an error
+					; error 05 is OK (OUT OF DATA)
+					; because we try to read too much
+	ldy	#$a
+	lda	(FILEML),Y
+	cmp	#5
+	beq	now_close
 
+	jmp	error_read
+
+now_close:
 	jsr	dos33_close		; close file
-
-	clc
+	bcs	error_close
 
 	rts
 
+error_open:
+	lda	#$f5
+	brk
+error_read:
+	ldy	#$a
+	lda	(FILEML),y
+	tay
+	lda	#$f6
+	brk
+error_close:
+	lda	#$f7
+	brk
+
 ;=================================
 ; get_dos_buffer
 ;=================================
@@ -224,6 +249,7 @@ dos33_close:
 	sta    (FILEML),y
 
 	jsr    filemanager_interface
+	bcs	error_close
 
 	ldy    #0		    	; mark dos buffer as free again
 	tya
@@ -246,7 +272,7 @@ dos33_read:
 
 	ldy   #6			; point to number of bytes to read
 	lda   #<read_size
-	sta   (FILEML),y		; we want to read 255 bytes
+	sta   (FILEML),y		; we want to read read_size bytes
 	iny
 	lda   #>read_size
 	sta   (FILEML),y
@@ -258,7 +284,7 @@ dos33_read:
 	lda   #>disk_buff
 	sta   (FILEML),y
 
-	bne   filemanager_interface     ; same as JMP
+	jmp	filemanager_interface
 
 filename:
 ; OUT.0
diff --git a/chiptune_player/README.chiptune b/chiptune_player/README.chiptune
index 1cc76fdf..5cb355e1 100644
--- a/chiptune_player/README.chiptune
+++ b/chiptune_player/README.chiptune
@@ -342,3 +342,8 @@ Thought it only took 1s max?  Not in face of interrupts.
 	
 	TIME_TAKEN ($88) stores how long took to decode
 		INTRO2: 60@19, 60@36, 62@50 61@1:03 61@1:32 60@2:05 61@2:32
+
++ Our old friend, forget the # so we're comparing against some random
+	zero page value rather than a constsant
+
++ Related, the accidentally put in a $ when I meant for it to be decimal.
diff --git a/chiptune_player/chiptune_player.s b/chiptune_player/chiptune_player.s
index 9bb0a456..e9810ace 100644
--- a/chiptune_player/chiptune_player.s
+++ b/chiptune_player/chiptune_player.s
@@ -132,18 +132,19 @@ mockingboard_found:
 
 	jsr	new_song
 
+;	jsr	increment_file		; debug
+;	jsr	new_song
+
+;	cli
+
 
-	lda	#<UNPACK_BUFFER		; set input pointer
-	sta	INL
-	lda	#>UNPACK_BUFFER
-	sta	INH
 
 
 	;============================
 	; Enable 6502 interrupts
 	;============================
 
-	;cli		; clear interrupt mask
+	cli		; clear interrupt mask
 
 
 	;============================
@@ -175,7 +176,7 @@ check_copy_loop:
 
 	inc     COPY_OFFSET     ; (opt: make subtract?)                 ; 5
 
-	lda	#$14
+	lda	#14		; NOT HEX URGH!
 	cmp	COPY_OFFSET
 	bne	check_copy_loop
 
@@ -232,6 +233,8 @@ done_play:
 	jsr	increment_file
 	jsr	new_song
 
+	cli
+
 	jmp	main_loop
 
 forever_loop:
@@ -347,6 +350,10 @@ read_size	EQU	$4000
 	adc	#0
 	sta	LZ4_SRC+1
 
+	lda	#<UNPACK_BUFFER		; set input pointer
+	sta	INL
+	lda	#>UNPACK_BUFFER
+	sta	INH
 
 	; Decompress first chunks
 
@@ -361,8 +368,6 @@ read_size	EQU	$4000
 
 	jsr	setup_next_subsong
 
-	cli	; start playing
-
 	rts
 
 	;=================
@@ -510,7 +515,7 @@ filename_found:
 increment_file:
 	inc	WHICH_FILE
 	lda	WHICH_FILE
-	cmp	NUM_FILES
+	cmp	#NUM_FILES
 	bne	done_increment
 	lda	#0
 	sta	WHICH_FILE
diff --git a/chiptune_player/zp.inc b/chiptune_player/zp.inc
index ac577981..8107fcaa 100644
--- a/chiptune_player/zp.inc
+++ b/chiptune_player/zp.inc
@@ -27,6 +27,9 @@ COLOR	EQU $30
 ; dos33 zero page = 26-2f, 35-38, 3e 3f 40-4d 
 ; overlap applesoft  67-6a,6f,70,af,b0,ca-cd,d8 
 
+
+; DOS33: Confirmed kills $68
+
 RWTSL		EQU $60
 RWTSH		EQU $61
 DOSBUFL		EQU $62
@@ -35,8 +38,8 @@ FILEML		EQU $64
 FILEMH		EQU $65
 				;TURNING	EQU $60
 				;SCREEN_X	EQU $61		; not used?
-SCREEN_Y	EQU $67
-WHICH_FILE	EQU $68
+				;SCREEN_Y	EQU $62
+
 
 				;ANGLE		EQU $63
 				;HORIZ_SCALE_I	EQU $64
@@ -95,6 +98,8 @@ C_COLOR		EQU $85
 COPY_TIME	EQU $86
 DECOMPRESS_TIME	EQU $87
 TIME_TAKEN	EQU $88
+SCREEN_Y	EQU $89
+WHICH_FILE	EQU $8A
 				;NUM2L		EQU $80
 				;NUM2H		EQU $81
 				;RESULT		EQU $82 ; 83,84,85