diff --git a/doc/ca65.sgml b/doc/ca65.sgml
index 37349f409..360b0bab2 100644
--- a/doc/ca65.sgml
+++ b/doc/ca65.sgml
@@ -439,6 +439,15 @@ The assembler accepts
       <tt><ref id=".P4510" name=".P4510"></tt> command was given).
 </itemize>
 
+On 6502-derived platforms the <tt/BRK/ instruction has an optional signature
+byte. If omitted, the assembler will only produce only 1 byte.
+
+<tscreen><verb>
+                brk                     ; 1-byte:  $00
+                brk     $34             ; 2-bytes: $00 $34
+                brk     #$34            ; 2-bytes: $00 $34
+</verb></tscreen>
+
 
 <sect1>65816 mode<p>
 
@@ -456,6 +465,17 @@ mnemonics:
 <item><tt>TSA</tt> is an alias for <tt>TSC</tt>
 </itemize>
 
+The <tt/MVN/ and <tt/MVP/ instructions accept two different argument forms.
+Either two bank bytes may be given with a <tt/#/ prefix,
+or two far addresses whose high byte will be used.
+
+<tscreen><verb>
+                mvn     #^src, #^dst       ; bank of src to bank of dst
+                mvn     src, dst           ; bank of src to bank of dst
+                mvp     #$12, #$78         ; bank $12 to $78
+                mvp     $123456, $789ABC   ; bank $12 to $78
+</verb></tscreen>
+
 
 <sect1>6502X mode<label id="6502X-mode"><p>
 
diff --git a/src/ca65/instr.c b/src/ca65/instr.c
index 745072a09..b72be6711 100644
--- a/src/ca65/instr.c
+++ b/src/ca65/instr.c
@@ -181,7 +181,7 @@ static const struct {
         { "BMI",  0x0020000, 0x30, 0, PutPCRel8 },
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
         { "CLC",  0x0000001, 0x18, 0, PutAll },
@@ -252,7 +252,7 @@ static const struct {
         { "BMI",  0x0020000, 0x30, 0, PutPCRel8 },
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
         { "CLC",  0x0000001, 0x18, 0, PutAll },
@@ -342,7 +342,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x12, 0, PutPCRel8 },      /* DTV */
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
         { "CLC",  0x0000001, 0x18, 0, PutAll },
@@ -418,7 +418,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x80, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
         { "CLC",  0x0000001, 0x18, 0, PutAll },
@@ -510,7 +510,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x80, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
         { "CLC",  0x0000001, 0x18, 0, PutAll },
@@ -622,7 +622,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x80, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BSR",  0x0040000, 0x63, 0, PutPCRel4510 },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
@@ -747,7 +747,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x80, 0, PutPCRel8 },
-        { "BRK",  0x0000005, 0x00, 6, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BRL",  0x0040000, 0x82, 0, PutPCRel16 },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
@@ -756,7 +756,7 @@ static const struct {
         { "CLI",  0x0000001, 0x58, 0, PutAll },
         { "CLV",  0x0000001, 0xb8, 0, PutAll },
         { "CMP",  0x0b8f6fc, 0xc0, 0, PutAll },
-        { "COP",  0x0000004, 0x02, 6, PutAll },
+        { "COP",  0x0800005, 0x02, 6, PutAll },
         { "CPA",  0x0b8f6fc, 0xc0, 0, PutAll },   /* == CMP */
         { "CPX",  0x0c0000c, 0xe0, 1, PutAll },
         { "CPY",  0x0c0000c, 0xc0, 1, PutAll },
@@ -833,7 +833,7 @@ static const struct {
         { "TYA",  0x0000001, 0x98, 0, PutAll },
         { "TYX",  0x0000001, 0xbb, 0, PutAll },
         { "WAI",  0x0000001, 0xcb, 0, PutAll },
-        { "WDM",  0x0000004, 0x42, 6, PutAll },
+        { "WDM",  0x0800004, 0x42, 6, PutAll },
         { "XBA",  0x0000001, 0xeb, 0, PutAll },
         { "XCE",  0x0000001, 0xfb, 0, PutAll }
     }
@@ -909,7 +909,7 @@ static const struct {
         { "BNE",  0x0020000, 0xd0, 0, PutPCRel8 },
         { "BPL",  0x0020000, 0x10, 0, PutPCRel8 },
         { "BRA",  0x0020000, 0x80, 0, PutPCRel8 },
-        { "BRK",  0x0000001, 0x00, 0, PutAll },
+        { "BRK",  0x0800005, 0x00, 6, PutAll },
         { "BSR",  0x0020000, 0x44, 0, PutPCRel8 },
         { "BVC",  0x0020000, 0x50, 0, PutPCRel8 },
         { "BVS",  0x0020000, 0x70, 0, PutPCRel8 },
diff --git a/test/asm/listing/109-brk-signature.s b/test/asm/listing/109-brk-signature.s
new file mode 100644
index 000000000..e9c23dd63
--- /dev/null
+++ b/test/asm/listing/109-brk-signature.s
@@ -0,0 +1,45 @@
+; test of optional signature byte for BRK on all 6502-derived CPUs
+; and also COP on 65C816
+
+.setcpu "6502"
+brk ; 1 byte
+brk 0 ; 2 bytes
+brk $60 ; 2 bytes
+brk #$60 ; 2 bytes
+
+.setcpu "6502X"
+brk
+brk $60
+brk #$60
+
+.setcpu "6502DTV"
+brk
+brk $60
+brk #$60
+
+.setcpu "65SC02"
+brk
+brk $60
+brk #$60
+
+.setcpu "65816"
+brk
+brk $60
+brk #$60
+cop
+cop $60
+cop #$60
+; WDM is a NOP that gives +2 PC, probably not useful to make its signature byte optional
+;wdm
+wdm $60
+wdm #$60
+
+.setcpu "4510"
+brk
+brk $60
+brk #$60
+
+.setcpu "HuC6280"
+brk
+brk $60
+brk #$60
diff --git a/test/asm/listing/ref/109-brk-signature.bin-ref b/test/asm/listing/ref/109-brk-signature.bin-ref
new file mode 100644
index 000000000..0eaa09faa
Binary files /dev/null and b/test/asm/listing/ref/109-brk-signature.bin-ref differ