diff --git a/avr/modules/flash/flash_rsp.asm b/avr/modules/flash/flash_rsp.asm
index c7cfa99..49b6936 100644
--- a/avr/modules/flash/flash_rsp.asm
+++ b/avr/modules/flash/flash_rsp.asm
@@ -29,7 +29,6 @@ flashSendFlashResponse:
   ; send flash ready message
   ldi xl, LOW(flashSendBuffer)
   ldi xh, HIGH(flashSendBuffer)
-  clr r16
   rcall flashWriteFlashRsp         ; (R16, R17, R18, R19, R20)
   rjmp flashSendPacketUntilSuccess ; (R15, R16, R17, R21, R22, X)
 
@@ -48,17 +47,17 @@ flashSendFlashResponse:
 
 flashWriteFlashRsp:
   clr r18
-  st X+, r18 ; dest address (unused)
-  ldi r18, 3 ; msg code+src address+one payload byte
-  st X+, r18 ; msg len
+  st X+, r18  ; dest address (unused)
+  ldi r18, 3  ; msg code+src address+one payload byte
+  st X+, r18  ; msg len
   ldi r17, CPRO_CMD_FLASH_RSP
-  st X+, r17 ; msg code
+  st X+, r17  ; msg code
   clr r17
-  st X+, r17 ; src address (not used)
-  st X, r16  ; payload byte
-  sbiw xh:xl, 4
-  rcall com2CalcAndAddChecksumByte ; (R16, R17, R18, R19, R20, X)
+  st X+, r17  ; src address (not used)
+  st X+, r16  ; payload byte
   sbiw xh:xl, 5
+  rcall com2CalcAndAddChecksumByte ; (R16, R17, R18, R19, R20, X)
+  sbiw xh:xl, 6
   ret