diff --git a/src/passport.a b/src/passport.a
index abd9862..1ebbeb3 100755
--- a/src/passport.a
+++ b/src/passport.a
@@ -800,6 +800,7 @@ _applyToAll
          !source "patchers/davidsonforth.a"     ; gIsDavidson only
          !source "patchers/davidsonasm.a"       ; gIsDavidson only
          !source "patchers/ssi.a"               ; gIsRDOS13 only
+         !source "patchers/rdosfmt.a"           ; gIsRDOS13 only
 
          lda   gPatchCount
          beq   .nopatches
diff --git a/src/patchers/rdos13.a b/src/patchers/rdos13.a
index 3ef1dcb..8f043f8 100644
--- a/src/patchers/rdos13.a
+++ b/src/patchers/rdos13.a
@@ -30,38 +30,33 @@
          !byte $48         ;PHA
          !byte $68         ;PLA
 
-         lda   #$0A
-         ldx   #$16
-         ldy   #1
-         jsr   modify
-         !byte $56
+         lda   #$56
+         sta   (BASEPAGE * $100) + $9A3
+         sta   (BASEPAGE * $100) + $A16
 
-         lda   #$0A
-         ldx   #$2B
-         ldy   #2
-         jsr   modify
-         !byte $23,$B8
+         lda   #$23
+         sta   (BASEPAGE * $100) + $A2B
+         sta   (BASEPAGE * $100) + $A3C
+         sta   (BASEPAGE * $100) + $A4C
 
-         lda   #$0A
-         ldx   #$3C
-         ldy   #2
-         jsr   modify
-         !byte $23,$B8
+         lda   #$B8
+         sta   (BASEPAGE * $100) + $A2C
+         sta   (BASEPAGE * $100) + $A3D
+         sta   (BASEPAGE * $100) + $A4D
 
-         lda   #$0A
-         ldx   #$4C
-         ldy   #2
-         jsr   modify
-         !byte $23,$B8
-
-;enable 16-sector address prologue
+;enable 16-sector address prologue as needed
 
          lda   #$0A
          ldx   #$75
          ldy   #2
+         jsr   compare
+         !byte $C9,$D5     ;CMP #$D5
+         bcc   +
+         ldy   #2
          jsr   modify
          !byte $C9,$D5     ;CMP #$D5
 
++
          lda   #$0A
          ldx   #$8B
          ldy   #1
diff --git a/src/patchers/rdosfmt.a b/src/patchers/rdosfmt.a
new file mode 100644
index 0000000..c5a825c
--- /dev/null
+++ b/src/patchers/rdosfmt.a
@@ -0,0 +1,38 @@
+;-------------------------------
+; #RDOS format interception
+; support disk tools that format 13-sectors
+;
+; module by qkumba
+;-------------------------------
+!zone {
+         bit   gMode      ; nothing to do here in verify-only mode
+         bpl   .exit
+         lda   gIsRDOS13
+         bne   .exit
+
+         ldy   #$0F
+         jsr   SearchTrack
+         !byte $A9,$D4    ; LDA #$D4
+         !byte $20,$CC,$09; JSR $09CC
+         !byte $A9,$AA    ; LDA #$AA
+         !byte $20,$CD,$09; JSR $09CD
+         !byte $A9,$B7    ; LDA #$B7
+         !byte $20,$CD,$09; JSR $09CD
+         bcs   .exit
+
+         inx
+         ldy   #1
+         jsr   modify
+         !byte $D5
+         pha
+         txa
+         clc
+         adc   #9
+         tax
+         pla
+         ldy   #1
+         jsr   modify
+         !byte $96
+
+.exit
+}