diff --git a/apps/lib/parse.asm b/apps/lib/parse.asm
index 103c005..9536379 100644
--- a/apps/lib/parse.asm
+++ b/apps/lib/parse.asm
@@ -22,42 +22,6 @@ parseHex:
 	ret
 
 
-; Parses 2 characters of the string pointed to by HL and returns the numerical
-; value in A. If the second character is a "special" character (<0x21) we don't
-; error out: the result will be the one from the first char only.
-; HL is set to point to the last char of the pair.
-;
-; On success, the carry flag is reset. On error, it is set.
-parseHexPair:
-	push	bc
-
-	ld	a, (hl)
-	call	parseHex
-	jr	c, .end		; error? goto end, keeping the C flag on
-	rla \ rla \ rla \ rla	; let's push this in MSB
-	ld	b, a
-	inc	hl
-	ld	a, (hl)
-	cp	0x21
-	jr	c, .single	; special char? single digit
-	call	parseHex
-	jr	c, .end		; error?
-	or	b		; join left-shifted + new. we're done!
-	; C flag was set on parseHex and is necessarily clear at this point
-	jr	.end
-
-.single:
-	; If we have a single digit, our result is already stored in B, but
-	; we have to right-shift it back.
-	ld	a, b
-	and	0xf0
-	rra \ rra \ rra \ rra
-	dec	hl
-
-.end:
-	pop	bc
-	ret
-
 ; Parse the decimal char at A and extract it's 0-9 numerical value. Put the
 ; result in A.
 ;
@@ -142,40 +106,35 @@ parseDecimal:
 
 ; Parse string at (HL) as a hexadecimal value without the "0x" prefix and
 ; return value in DE.
+; HL is advanced to the character following the last successfully read char.
 ; Sets Z on success.
 parseHexadecimal:
-	push	hl
-	call	strlen
-	cp	3
-	jr	c, .single
-	cp	4
-	jr	c, .doubleShort	; 0x123
-	cp	5
-	jr	c, .double	; 0x1234
-	; too long, error
-	jr	.error
-.double:
-	call	parseHexPair
-	jr	c, .error
-	inc	hl			; now HL is on first char of next pair
-	ld	d, a
-	jr	.single
-.doubleShort:
 	ld	a, (hl)
 	call	parseHex
-	jr	c, .error
-	inc	hl			; now HL is on first char of next pair
-	ld	d, a
-.single:
-	call	parseHexPair
-	jr	c, .error
+	jp	c, unsetZ	; we need at least one char
+	push	bc
+	ld	de, 0
+	ld	b, 0
+.loop:
+	; we push to B to verify overflow
+	rl	e \ rl d \ rl b
+	rl	e \ rl d \ rl b
+	rl	e \ rl d \ rl b
+	rl	e \ rl d \ rl b
+	or	e
 	ld	e, a
-	cp	a			; ensure Z
-	jr	.end
-.error:
-	call	unsetZ
+	; did we overflow?
+	ld	a, b
+	or	a
+	jr	nz, .end	; overflow, NZ already set
+	; next char
+	inc	hl
+	ld	a, (hl)
+	call	parseHex
+	jr	nc, .loop
+	cp	a		; ensure Z
 .end:
-	pop	hl
+	pop	bc
 	ret
 
 ; Parse string at (HL) as a binary value (010101) without the "0b" prefix and
@@ -271,7 +230,9 @@ parseLiteral:
 	ret			; Z already set
 
 .hex:
+	push	hl
 	call	parseHexadecimal
+	pop	hl
 	jr	.hexOrBinEnd
 
 .bin:
diff --git a/apps/zasm/main.asm b/apps/zasm/main.asm
index 02a1a72..59e3f31 100644
--- a/apps/zasm/main.asm
+++ b/apps/zasm/main.asm
@@ -25,30 +25,32 @@
 zasmMain:
 	; Parse args in (HL)
 	; blkdev in
-	call	parseHexPair	; --> A
-	jr	c, .badargs
+	call	parseHexadecimal	; --> DE
+	jr	nz, .badargs
+	ld	a, e
 	ld	de, IO_IN_BLK
 	call	blkSel
-	inc	hl		; char following last hex char
 
 	; blkdev in
 	call	rdWS
 	jr	nz, .badargs
-	call	parseHexPair	; --> A
-	jr	c, .badargs
+	call	parseHexadecimal	; --> DE
+	jr	nz, .badargs
+	ld	a, e
 	ld	de, IO_OUT_BLK
 	call	blkSel
-	inc	hl		; char following last hex char
 
 	; .org high byte
+	ld	e, 0			; in case we .skipOrgSet
 	call	rdWS
 	jr	nz, .skipOrgSet		; no org argument
-	call	parseHexPair	; --> A
-	jr	c, .badargs
+	call	parseHexadecimal	; --> DE
+	jr	nz, .badargs
 
 .skipOrgSet:
 	; Init .org with value of E
 	; Save in "@" too
+	ld	a, e
 	ld	(ZASM_ORG+1), a		; high byte of .org
 	ld	(DIREC_LASTVAL+1), a
 	xor	a
diff --git a/recipes/sms/romasm/glue.asm b/recipes/sms/romasm/glue.asm
index b583e48..dea11b8 100644
--- a/recipes/sms/romasm/glue.asm
+++ b/recipes/sms/romasm/glue.asm
@@ -16,7 +16,6 @@
 	jp	upcase
 	jp	findchar
 	jp	parseHex
-	jp	parseHexPair
 	jp	blkSel
 	jp	blkSet
 	jp	fsFindFN
@@ -145,9 +144,9 @@ basFindCmdExtra:
 	jp	basPgmHook
 .mycmds:
 	.db "ed", 0
-	.dw 0x1e00
+	.dw 0x1f00
 	.db "zasm", 0
-	.dw 0x2300
+	.dw 0x2400
 	.db 0xff
 
 f0GetB:
@@ -166,13 +165,13 @@ f1PutB:
 	ld	ix, FS_HANDLES+FS_HANDLE_SIZE
 	jp	fsPutB
 
-; last time I checked, PC at this point was 0x1df8. Let's give us a nice margin
+; last time I checked, PC at this point was 0x1e92. Let's give us a nice margin
 ; for the start of ed.
-.fill 0x1e00-$
+.fill 0x1f00-$
 .bin "ed.bin"
 
-; Last check: 0x22dd
-.fill 0x2300-$
+; Last check: 0x23b0
+.fill 0x2400-$
 .bin "zasm.bin"
 
 .fill 0x7ff0-$
diff --git a/recipes/sms/romasm/user.h b/recipes/sms/romasm/user.h
index 5d7ff7b..ff4456b 100644
--- a/recipes/sms/romasm/user.h
+++ b/recipes/sms/romasm/user.h
@@ -14,7 +14,6 @@
 .equ	upcase			@+3
 .equ	findchar		@+3
 .equ	parseHex		@+3
-.equ	parseHexPair	@+3
 .equ	blkSel			@+3
 .equ	blkSet			@+3
 .equ	fsFindFN		@+3
diff --git a/tools/tests/unit/test_parse.asm b/tools/tests/unit/test_lib_parse.asm
similarity index 71%
rename from tools/tests/unit/test_parse.asm
rename to tools/tests/unit/test_lib_parse.asm
index ae77408..788c01e 100644
--- a/tools/tests/unit/test_parse.asm
+++ b/tools/tests/unit/test_lib_parse.asm
@@ -13,7 +13,7 @@ test:
 	ld	sp, 0xffff
 
 	call	testParseHex
-	call	testParseHexPair
+	call	testParseHexadecimal
 
 	; success
 	xor	a
@@ -40,24 +40,30 @@ testParseHex:
 	call	nexttest
 	ret
 
-testParseHexPair:
+testParseHexadecimal:
 	ld	hl, .s99
-	call	parseHexPair
-	jp	c, fail
+	call	parseHexadecimal
+	jp	nz, fail
+	ld	a, e
 	cp	0x99
 	jp	nz, fail
 	call	nexttest
 
 	ld	hl, .saB
-	call	parseHexPair
-	jp	c, fail
+	call	parseHexadecimal
+	jp	nz, fail
+	ld	a, e
 	cp	0xab
 	jp	nz, fail
 	call	nexttest
 
+	; The string "Foo" will not cause a failure. We will parse up to "o"
+	; and then stop.
 	ld	hl, .sFoo
-	call	parseHexPair
-	jp	nc, fail
+	call	parseHexadecimal
+	jp	nz, fail
+	ld	a, e
+	cp	0xf
 	call	nexttest
 	ret