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/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
+}