diff --git a/src/id/inspect0.a b/src/id/inspect0.a
index 5105dad..ac4d98c 100755
--- a/src/id/inspect0.a
+++ b/src/id/inspect0.a
@@ -221,6 +221,7 @@ IDBootloader
          bcs   +
          lda   #s_micrograms
          jsr   PrintByID
+         bcc   .useuniv   ; always branches
 ;
 ; Quick-DOS
 ;
@@ -228,6 +229,14 @@ IDBootloader
          bcs   +
          lda   #s_quickdos
          jsr   PrintByID
+         bcc   .useuniv   ; always branches
+;
+; RDOS
+;
++        jsr   IDRDOS
+         bcs   +
+         lda   #s_rdos
+         jsr   PrintByID
 
 +
 .useuniv
diff --git a/src/id/rdos.a b/src/id/rdos.a
new file mode 100644
index 0000000..e3902e1
--- /dev/null
+++ b/src/id/rdos.a
@@ -0,0 +1,26 @@
+;-------------------------------
+; IDRDOS
+; identify RDOS 16-sector bootloader
+;
+; in:  $0800..$08FF contains T00,S00
+;      first page of track buffer also contains T00,S00
+; out: C clear if RDOS 16-sector bootloader found
+;      C set otherwise
+;      all registers clobbered
+;      all other flags clobbered
+;-------------------------------
+!zone {
+IDRDOS
+         lda   #$00
+         ldx   #$00
+         ldy   #$0E
+         jsr   compare    ; if T00,S00,$00 ==
+         !byte $01
+         !byte $A9,$60    ; LDA #$60
+         !byte $8D,$01,$08; STA $0801
+         !byte $A2,$00    ; LDX #$00
+         !byte $A0,$1F    ; LDY #$1F
+         !byte $B9,$00,$08; LDA $0800,Y
+         !byte $49        ; EOR
+         rts
+}
diff --git a/src/passport.a b/src/passport.a
index 59064f4..ffba8f8 100755
--- a/src/passport.a
+++ b/src/passport.a
@@ -155,6 +155,7 @@ FirstMover
          !source "id/dos33.a"
          !source "id/prodos.a"
          !source "id/pascal.a"
+         !source "id/rdos.a"
          !source "id/jsr8b3.a"
          !source "id/mecc.a"
          !source "id/datasoft.a"
diff --git a/src/patchers/rwtslog.a b/src/patchers/rwtslog.a
index 7c650e0..c72df1e 100644
--- a/src/patchers/rwtslog.a
+++ b/src/patchers/rwtslog.a
@@ -11,36 +11,45 @@
 ; disk allows either $D4 or $D5 for the
 ; first address prologue nibble
 ;-------------------------------
-         lda   gIsRWTS    ; if DOS 3.3 RWTS
-         bne   +
+; DOS 3.3 variant
          lda   #$03
          sta   gDisplayBytes
          ldx   #$4F
          ldy   #$0A
-         jsr   compare    ; and T00,S03,$4F ==
+         jsr   compare    ; if T00,S03,$4F ==
          !byte $BD,$8C,$C0
          !byte $10,$FB
          !byte $4A
          !byte WILDCARD,$6A
          !byte $D0,$EF
-         bcs   +
+         bcc   .yeslsr
+; RDOS variant
+         ldx   #$4D
+         ldy   #$0A
+         jsr   compare    ; or T00,S03,$4D ==
+         !byte $BD,$8C,$C0
+         !byte $10,$FB
+         !byte $4A
+         !byte WILDCARD,$6A
+         !byte $D0,$EF
+         bcs   .endlsr
+.yeslsr
          lda   #s_lsr6a
          jsr   PrintByID
          inc   gPatchCount
-+
+.endlsr
 
 ;-------------------------------
 ; RWTS "CMP #$08 / BCS" identification
 ; disk allows either $DE or a timing bit
 ; for the first address epilogue nibble
 ;-------------------------------
-         lda   gIsRWTS    ; if DOS 3.3 RWTS
-         bne   +
+; DOS 3.3 variant
          lda   #$03
          sta   gDisplayBytes
          ldx   #$8B
          ldy   #$15
-         jsr   compare    ; and T00,S03,$8B ==
+         jsr   compare    ; if T00,S03,$8B ==
          !byte $BD,$8C,$C0
          !byte $10,$FB
          !byte $C9,$DE
@@ -53,53 +62,57 @@
          !byte $EA
          !byte $18
          !byte $60
-         bcs   +
+         bcc   .yesbcs
+; RDOS variant
+         ldx   #$89
+         ldy   #$11
+         jsr   compare    ; or T00,S03,$89 ==
+         !byte $BD,$8C,$C0
+         !byte $10,$FB
+         !byte $C9,$DE
+         !byte $F0,$09
+         !byte $48
+         !byte $68
+         !byte $BD,$8C,$C0
+         !byte $C9,$80
+         !byte $B0
+         bcs   .endbcs
+.yesbcs
          lda   #s_bcs08
          jsr   PrintByID
          inc   gPatchCount
-+
+.endbcs
 
 ;-------------------------------
 ; RWTS "CMP / BNE 0" identification
 ; disk allows any value for
 ; for the first address epilogue nibble
 ;-------------------------------
-         lda   gIsRWTS    ; if DOS 3.3 RWTS
-         bne   +
+; DOS 3.3 variant
          lda   #$03
          sta   gDisplayBytes
          ldx   #$8B
          ldy   #$09
-         jsr   compare    ; and T00,S03,$8B ==
+         jsr   compare    ; if T00,S03,$8B ==
          !byte $BD,$8C,$C0
          !byte $10,$FB
          !byte $C9,WILDCARD
          !byte $D0,$00
-         bcs   +
-         lda   #s_cmpbne0
-         jsr   PrintByID
-         inc   gPatchCount
-+
-
-;-------------------------------
-; RWTS "CMP / BNE 0" identification (David-DOS variant)
-; disk allows any value for
-; for the first address epilogue nibble
-;-------------------------------
-         lda   gIsDavidDOS ; if David-DOS bootloader
-         bne   +
+         bcc   .yesbne0
+; David-DOS variant
          lda   #$05
          sta   gDisplayBytes
          ldx   #$8B
          ldy   #$09
-         jsr   compare    ; and T00,S05,$8B ==
+         jsr   compare    ; or T00,S05,$8B ==
          !byte $BD,$8C,$C0
          !byte $10,$FB
          !byte $C9,WILDCARD
          !byte $D0,$00
-         bcs   +
+         bcs   .endbne0
+.yesbne0
          lda   #s_cmpbne0
          jsr   PrintByID
          inc   gPatchCount
-+
+.endbne0
 }
diff --git a/src/strings/en.a b/src/strings/en.a
index 41c4fa8..6d77dac 100755
--- a/src/strings/en.a
+++ b/src/strings/en.a
@@ -107,7 +107,8 @@ s_advint =     $58
 s_dos32b0 =    $59
 s_bootwrite =  $5A
 s_rwtswrite =  $5B
-STRINGCOUNT =  $5C
+s_rdos =       $5C
+STRINGCOUNT =  $5D
 
 !zone {
 StringTable
@@ -203,6 +204,7 @@ StringTable
          !word .dos32boot0
          !word .bootwrite
          !word .rwtswrite
+         !word .rdos
 ;
 ; Text can contain substitution strings, which
 ; are replaced by current values at runtime. Each
@@ -228,7 +230,7 @@ StringTable
 ; can be set directly before calling PrintByID.
 ;
 .header
-         !text "Passport by 4am               2017-09-05",$00
+         !text "Passport by 4am               2017-09-07",$00
 .mainmenu
          !text "________________________________________",$8D,$8D,$8D,$8D,$8D,$8D,$8D
          !text "              "
@@ -506,4 +508,6 @@ StringTable
          !text "bootloader",$8D,$00
 .rwtswrite
          !text "T00,S02 Writing built-in RWTS",$8D,$00
+.rdos
+         !text "T00,S00 Found RDOS bootloader",$8D,$00
 }