diff --git a/firmware/util.s b/firmware/util.s
index 6e911c0..8020ec3 100644
--- a/firmware/util.s
+++ b/firmware/util.s
@@ -43,7 +43,7 @@ LC604:  jsr     BELL
 LC607:  jsr     GETLNZ          ; start new line and take input
         lda     #$00
         sta     $F2
-LC60E:  sta     KBDSTRB         ; clear keyboard strobe
+PARSER: sta     KBDSTRB         ; clear keyboard strobe
         sta     $F3
         ldy     $F2
         jsr     GETNUM          ; parse hex into A2, A has last char xor $b0
@@ -70,13 +70,13 @@ LC60E:  sta     KBDSTRB         ; clear keyboard strobe
         bne     LC604           ; BEEP and prompt for new input
         brk                     ; 'Q' exits out
 
-; 'R': recalibrate by seeking track $00 from track $50
-CMD_R:  lda     #$50            ; set starting track to #$50
+; 'R': recalibrate by seeking track 0 from track 80
+CMD_R:  lda     #80             ; set starting track
         sta     $FC             ; store accumulator as 'current' track at $FC
         txa                     ; set accumulator to 0
         adc     #$00            ; inc A (carry still set from CMP #$EB)
         sta     $F3             ; set ($F3)=01
-        lda     #$00            ; pass target track #$00 through accumulator
+        lda     #$00            ; pass target track 0 through accumulator
         beq     LC651           ; branch to end of 'S' command to finish
 
 ; 'S': seek logical-track index in A2L ('22S' seeks logical track $22)
@@ -92,8 +92,9 @@ CMD_Z:  lda     A2L             ; load logical track-index from A2L
         sta     $F1             ; store as target track in $F1
         ldy     #$00            ; value to stored at $09 = #$00
         beq     CMD_MX          ; branch to 'M' command for next step
+
         ; temporarily stop motor, then branch to turn it on again
-LC660:  lda     #$50
+STOP_MOTOR:  lda     #$50
         jsr     MON_WAIT
         sta     MOTOROFF,x
         ldy     A2L
@@ -103,11 +104,11 @@ LC66A:  jsr     MON_WAIT
         bmi     LC68E
 
 ; EXIT THRU GIFT SHOP, current command finished, go back to parser
-LC672:  lda     #$00
-        beq     LC60E
+DONE:   lda     #$00
+        beq     PARSER
 
 ; 'W' command, write nibble-pattern in A2L (eg: "96W" writes 96 96 96...)
-CMD_W:  lda     A2L
+CMD_W:  lda     A2L             ; pattern to write
         sta     $FF
         ldy     #$0F
 
@@ -134,27 +135,29 @@ LC68E:  sta     MOTORON,x
         sta     Q7ON,x          ; start writing/erasing
 LC69D:  lda     $09             ; [3 cycles] reload saved Y byte
         asl     a               ; [2] shift-left to test second bit
-        bmi     LC660           ; [2] branch to stop motor for 'M' and 'X' and 'S' commands
+        bmi     STOP_MOTOR      ; [2] branch to stop motor for M/X/S commands
         nop
         nop
         lda     $FF             ; byte value to be written
-        sta     Q6ON,x          ; store into data register (wrong timing for Disk II, it would probably write $DD instead)
+        sta     Q6ON,x          ; store into data register
+                                ; (wrong timing for Disk II, it would probably
+                                ; write $DD instead)
         cmp     Q6OFF,x         ; [4] shift data-out
 LC6AC:  lda     KBD             ; get keypress
         eor     #$9B            ; ESC?
         bne     LC69D           ; if not, continue loop
         ldx     SLOTx16
         sta     Q7OFF,x
-LC6B8:  beq     LC672           ; all done, branch to branch-to-parser
+LC6B8:  beq     DONE           ; all done, branch to branch-to-parser
 LC6BA:  ldx     SLOTx16
         sta     MOTORON,x
 LC6BF:  ldy     $FC
 LC6C1:  cpy     $F0             ; compare track index in Y to target track (result in carry flag)
         bne     LC6E3           ; track doesn't match, go to stepper routine
-        lda     $F0             ; load current track into accumulator (redundant, same value is already in Y reg)
+        lda     $F0             ; load current track into A (why not tya?)
         sta     $FC             ; store current track
         lda     $09
-        bne     LC672           ; Y=00, branch for 'Z'
+        bne     DONE           ; Y=00, branch for 'Z'
         lda     $F0             ; exchange target track indexes in $F0 vs $F1
         ldy     $F1
         sta     $F1
@@ -172,14 +175,14 @@ LC6E7:  dey
         tya
         and     #$03            ; mask track to just 4 low bits, numbers 00-01-02-03
         asl     a               ; shift left, convert to stepper-motor phases 02-04-06-08
-        ora     SLOTx16         ; bitwise-OR to make it into a DEVSEL-relative IO address
-        tax                     ; move it into X reg for IO
+        ora     SLOTx16         ; bitwise-OR for DEVSEL-relative IO address
+        tax                     ; move it into X for IO
         lsr     a               ; shift right to make track number again
-        lsr     a               ; now shift low-bit into carry flag (odd vs even)
-        sta     STEPON,x        ; turn on stepper motor phase indicated in X reg
+        lsr     a               ; shift low-bit into carry flag (odd vs even)
+        sta     STEPON,x        ; turn on stepper motor phase indicated in X
         nop                     ; dead code
         nop
         lda     #$56
-        jsr     MON_WAIT        ; wait stepper delay (returns with A=00, carry set)
-        sta     STEPOFF,x       ; turn off stepper motor phase indicated in X reg
+        jsr     MON_WAIT        ; wait stepper delay (returns A=00, carry set)
+        sta     STEPOFF,x       ; turn off stepper motor phase indicated in X
         bcs     LC6C1           ; branch always