diff --git a/avr/flashproto.asm b/avr/flashproto.asm
index b70b85a..3dbbc51 100644
--- a/avr/flashproto.asm
+++ b/avr/flashproto.asm
@@ -69,27 +69,43 @@ bootLoader:
   ldi r16, Low(RAMEND)
   out SPL, r16             ; init LSB stack pointer
 
-  sbi DDRA, PORTA3 ; out
-;    sbi PINA, PORTA3 ; toggle
+  ; setup pins and interrupts
+  cbi COM_PORT_DATA, COM_PINNUM_DATA      ; disable internal pullup for DATA
+  cbi COM_DDR_DATA, COM_PINNUM_DATA       ; set DATA port as input
+
+  cbi COM_PORT_ATTN, COM_PINNUM_ATTN      ; disable internal pullup for ATTN
+  cbi COM_DDR_ATTN, COM_PINNUM_ATTN       ; set ATTN port as input
+
+
+  sbi DDRA, PORTA3  ; out
   cbi PORTA, PORTA3 ; on
-;    sbi PORTA, PORTA3 ; off
+  sbi DDRA, PORTA2  ; out (debug)
+  sbi PORTA, PORTA2 ; off  (debug)
+
   rcall flashReadUid
   sts flashUid, r18
   sts flashUid+1, r19
   sts flashUid+2, r20
   sts flashUid+3, r21
-  
+
+  ; wait for 3 secs before sending message
+  ldi r16, 30
+  rcall flashWaitForMulti100ms
+
   ; send flash ready message
   ldi xl, LOW(flashSendBuffer)
   ldi xh, HIGH(flashSendBuffer)
   rcall flashWriteFlashReady
   rcall flashSendPacketUntilSuccess
 
+  sbi PORTA, PORTA3 ; LED off
+
   ; wait up to 10s for incoming FLASH_START message
   ldi r16, CPRO_CMD_FLASH_START
   ldi r17, 100 ; 100*100ms=10s
   rcall flashWaitForSpecificMessageWithLed
   brcc bootLoader_startFirmware
+
   ; either FLASH_START or FLASH_END received
   cpi r16, CPRO_CMD_FLASH_START   ; not FLASH_START, no flashing requested
   brne bootLoader_startFirmware
@@ -97,11 +113,18 @@ bootLoader:
 
   ; try to start firmware
 bootLoader_startFirmware:
-  lds r20, firmwareStart
-  lds r21, firmwareStart+1
+  sbi PORTA, PORTA3 ; LED off
+  ldi r16, 20
+  rcall flashWaitForMulti100ms
+
+  ldi zl, LOW(firmwareStart*2)
+  ldi zh, HIGH(firmwareStart*2)
+  lpm r20, Z+
+  lpm r21, Z+
   mov r16, r20
   or r16, r21
   breq bootLoader ; restart boot loader
+
   ; jmp via stack
   push r20
   push r21
@@ -149,7 +172,7 @@ flashWaitForSpecificMessageWithLed_received:
 ;
 ; IN:
 ; - R16: msg command to wait for
-; - R17: time to wait for packet (in milliseconds) (low)
+; - R17: time to wait for packet (in milliseconds)
 ; OUT:
 ; - CFLAG: set if msg received, cleared on timeout
 ; - R16  : message type received
@@ -159,9 +182,11 @@ flashWaitForSpecificMessage:
   mov r1, r16                               ; expected message type
 
     ; wait for ATTN to go low
+
+flashWaitForSpecificMessage_loop0:
 flashWaitForSpecificMessage_loop1:
     ldi r16, 0                              ; wait for low
-    rcall flashWaitForAttnState1ms          ; (R24, R25)
+    rcall flashWaitForAttnState1ms          ; (R22, R24)
     brcs flashWaitForSpecificMessage_isLow
     dec r17
   brne flashWaitForSpecificMessage_loop1
@@ -193,14 +218,14 @@ flashWaitForSpecificMessage_waitAttnHigh:
   ; wait for ATTN to go high
 flashWaitForSpecificMessage_loop2:
     ldi r16, 0xff                           ; wait for high
-    rcall flashWaitForAttnState1ms          ; (R24, R25)
+    rcall flashWaitForAttnState1ms          ; (R22, R24)
     brcs flashWaitForSpecificMessage_isHigh
     dec r17
   brne flashWaitForSpecificMessage_loop2
   rjmp flashWaitForSpecificMessage_timeout
 
 flashWaitForSpecificMessage_isHigh:
-  rjmp flashWaitForSpecificMessage_loop1
+  rjmp flashWaitForSpecificMessage_loop0
 
 flashWaitForSpecificMessage_received:       ; R16 contains message type
   sec
@@ -218,18 +243,20 @@ flashWaitForSpecificMessage_timeout:
 ; - R16: expected state (0xff for high, 0 for low)
 ; OUT:
 ; - CFLAG: set if state reached, cleared otherwise
-; REGS: R24, R25
+; REGS: R24 (R22)
 
 flashWaitForAttnState1ms:
-  ldi r24, LOW(1000)
-  ldi r25, HIGH(1000)
-
+  ldi r24, 100
 flashWaitForAttnState1ms_loop:
-    in r17, COM_PIN_ATTN
-    eor r17, r16
-    andi r17, (1<<COM_PINNUM_ATTN)
+    push r17
+      in r17, COM_PIN_ATTN
+      eor r17, r16
+      andi r17, (1<<COM_PINNUM_ATTN)
+    pop r17
     breq flashWaitForAttnState1ms_stateReached
-    sbiw r25:r24, 1
+
+    Utils_WaitNanoSecs 10000, 0, r22              ; wait for 10us
+    dec r24
   brne flashWaitForAttnState1ms_loop
   clc
   ret
@@ -255,7 +282,6 @@ flashSendPacketUntilSuccess:
       pop xh
     pop xl
     brcc flashSendPacket_error
-    cbi PORTA, PORTA3 ; on
     ret
 flashSendPacket_error:
     rcall flashWaitForAttnHigh
@@ -298,17 +324,34 @@ flashWaitForAttnHigh_stillLow:
 flashWaitDependingOnUid:
   lds r16, flashUid
   tst r16
-  brne flashWaitForAttnHigh_waitLoop
+  brne flashWaitDependingOnUid_l1
   ldi r16, 17
-flashWaitForAttnHigh_waitLoop:        ; wait for up to 25s before trying again
-    rcall flashWaitFor100ms           ; (R18, R22, R24, R25)
-    sbi PINA, PORTA3                  ; toggle LED
+flashWaitDependingOnUid_l1:
+  rjmp flashWaitForMulti100ms
+
+
+
+; ---------------------------------------------------------------------------
+; wait for multiples of 100ms.
+;
+; IN:
+; - R16: number of 100ms loops
+; OUT:
+; - nothing
+; REGS: R16 (R18, R22, R24, R25)
+
+flashWaitForMulti100ms:
+flashWaitForMulti100ms_loop:
+    rcall flashWaitFor100ms      ; (R18, R22, R24, R25)
     dec r16
-  brne flashWaitForAttnHigh_waitLoop
+  brne flashWaitForMulti100ms_loop
   ret
 
 
 
+
+
+
 ; ---------------------------------------------------------------------------
 ; wait for 100 milliseconds.
 ;
@@ -335,14 +378,13 @@ flashWaitFor100ms_loop:
 ; - nothing
 ; OUT:
 ; - nothing
-; REGS: R24, R25 (R22)
+; REGS: R24 (R22)
 
 flashWaitFor1ms:
-  ldi r24, LOW(1000)
-  ldi r25, HIGH(1000)
+  ldi r24, 10
 flashWaitFor1ms_loop:
-    rcall com2WaitFor1000ns
-    sbiw r25:r24, 1
+    Utils_WaitNanoSecs 100000, 0, r22 ; wait for 100us
+    dec r24
   brne flashWaitFor1ms_loop
   ret
 
@@ -383,7 +425,7 @@ flashWriteFlashRsp:
 ; - X  : buffer to write to
 ; OUT:
 ; - nothing
-; MODIFIED REGS: R16 (R17, R18, R19, R20)
+; MODIFIED REGS: R16, Z (R17, R18, R19, R20)
 
 flashWriteFlashReady:
   clr r16
@@ -403,14 +445,16 @@ flashWriteFlashReady:
   st X+, r16
   lds r16, flashUid+3
   st X+, r16
-  lds r16, firmwareType
-  st X+, r16
-  lds r16, firmwareType+1
-  st X+, r16
-  lds r16, firmwareVersion
-  st X+, r16
-  lds r16, firmwareVersion+1
-  st X+, r16
+  ldi zl, low(firmwareType*2)
+  ldi zh, HIGH(firmwareType*2)
+  lpm r16, Z+
+  st X+, r16     ; firmwareType (low)
+  lpm r16, Z+
+  st X+, r16     ; firmwareType (high)
+  lpm r16, Z+ 
+  st X+, r16     ; firmwareVersion (low)
+  lpm r16, Z+ 
+  st X+, r16     ; firmwareVersion (high)
   ldi r16, LOW(PAGESIZE*2)
   st X+, r16
   ldi r16, HIGH(PAGESIZE*2)