diff --git a/avr/com.asm b/avr/com.asm
index 3e73342..470f095 100644
--- a/avr/com.asm
+++ b/avr/com.asm
@@ -38,6 +38,7 @@
 .equ COM_MSG_OFFS_MSGDATA         = 2
 
 .equ COM_CMD_PING                 = 1
+.equ COM_CMD_COMSENDSTATS         = 2
 
 
 ; ***************************************************************************
@@ -259,6 +260,90 @@ COM_EnqueuePing_error:
 
 
 
+; ---------------------------------------------------------------------------
+; Enqueue a COM Send stats packet.
+;
+; IN:
+; - R16: destination address
+; OUT:
+; - CFLAG: set if okay, clear otherwise
+; MODIFIED REGS: R16, R17, R20, X (R15, Y)
+
+COM_EnqueueComSendStats:
+  push r15
+    in r15, SREG
+    cli
+    push r16
+      rcall COM_AllocBufferAndGetXY ; (r16, r17, r21)
+    pop r16
+    brcc COM_EnqueueComSendStats_error
+    clr r17                         ; r17: XOR byte
+    ; write header (dest address, msg length)
+    st X+, r16                      ; destination address
+    eor r17, r16
+    ldi r16, 12                      ; 8 bytes payload
+    st X+, r16
+    eor r17, r16
+    ; write payload
+    ldi r16, COM_CMD_COMSENDSTATS
+    st X+, r16
+    eor r17, r16
+    lds r16, comAddress
+    st X+, r16
+    eor r17, r16
+  
+    lds r16, timerModuleCounterSecs
+    st X+, r16
+    eor r17, r16
+    lds r16, timerModuleCounterSecs+1
+    st X+, r16
+    eor r17, r16
+    lds r16, timerModuleCounterSecs+2
+    st X+, r16
+    eor r17, r16
+    lds r16, timerModuleCounterSecs+3
+    st X+, r16
+    eor r17, r16
+  
+    lds r16, comStatsPacketsOut
+    st X+, r16
+    eor r17, r16
+    lds r16, comStatsPacketsOut+1
+    st X+, r16
+    eor r17, r16
+    
+    lds r16, comStatsCollisions
+    st X+, r16
+    eor r17, r16
+    lds r16, comStatsCollisions+1
+    st X+, r16
+    eor r17, r16
+  
+    lds r16, comStatsAborted
+    st X+, r16
+    eor r17, r16
+    lds r16, comStatsAborted+1
+    st X+, r16
+    eor r17, r16
+  
+    ; store XOR byte
+    st X+, r17
+    ; mark buffer as enqueued with PRIO "info" (limited amount of retries)
+    ldi r20, COM_BUFFER_PRIO_INFO
+    rcall COM_EnqueuePacket      ; (R15, R16)
+    brcc COM_EnqueueComSendStats_error
+  pop r15
+  out SREG, r15
+  sec
+  ret
+COM_EnqueueComSendStats_error:
+  pop r15
+  out SREG, r15
+  clc
+  ret
+
+
+
 ; ---------------------------------------------------------------------------
 ; comHandleNextPacketInQueue
 ;
@@ -347,6 +432,11 @@ comHandleReceivedPacket_l2:
 comSendPacketHandleRepeat:
   in r15, SREG
   cli
+    cbi COM_PORT_ATTN, COM_PINNUM_ATTN             ; disable pullup on ATTN
+    cbi COM_DDR_ATTN, COM_PINNUM_ATTN              ; set ATTN as input
+    nop                                            ; needed to sample current input
+    sbis COM_PIN_ATTN, COM_PINNUM_ATTN             ; ATTN low?
+      rjmp comSendPacketHandleRepeat_adjustRepeat  ; jump if it is
     ldd r16, y+COM_BUFFER_OFFS_FLAGS
     rcall comSetupRepeat                           ; setup comRepeatCount if not already done (R16, R17)
     cbi COM_PORT_ATTN, COM_PINNUM_ATTN             ; set ATTN low
@@ -354,23 +444,25 @@ comSendPacketHandleRepeat:
     Utils_WaitNanoSecs COM_BIT_LENGTH, 0, r22      ; wait for one bit duration
     rcall comSendPacketHandleBuffer                ; (R16, R17, R21, R22)
     cbi COM_DDR_ATTN, COM_PINNUM_ATTN              ; release ATTN line
-    brcc comSendPacketHandleRepeat_adjustRepeat
+    brcc comSendPacketHandleRepeat_collision
     ; packet sent, adjust stats, release buffer
     ldi xl, LOW(comStatsPacketsOut)
     ldi xh, HIGH(comStatsPacketsOut)
     rcall comDeallocReadBufAndIncrCounter          ; (r16, r17, r18)
     rjmp comSendPacketHandleRepeat_retC
-comSendPacketHandleRepeat_adjustRepeat:
+comSendPacketHandleRepeat_collision:
     ; increment collisions counter
     ldi xl, LOW(comStatsCollisions)
     ldi xh, HIGH(comStatsCollisions)
-    clr r22
+    ldi r22, 1
     ld r16, x+
     ld r17, x
-    inc r16
+    add r16, r22
+    dec r22
     adc r17, r22
-    st -x, r17
-    st x, r16
+    st x, r17
+    st -x, r16
+comSendPacketHandleRepeat_adjustRepeat:
     ; decrement repeat counter (except for vital messages)
     lds r17, comRepeatCount
     cpi r17, COM_REPEAT_VITAL
@@ -445,13 +537,14 @@ comSetupRepeat_l99:
 
 comDeallocReadBufAndIncrCounter:
   rcall COM_BufferDeallocFront                    ; (r16, r17, r21)
-  clr r21
+  ldi r21, 1
   ld r16, x+
   ld r17, x
-  inc r16
+  add r16, r21
+  dec r21
   adc r17, r21
-  st -x, r17
-  st x, r16
+  st x, r17
+  st -x, r16
   sts comRepeatCount, r21                         ; set comRepeatCount to zero
   ret
 
@@ -829,7 +922,7 @@ COM_BufferAlloc:
   lds r16, comRecvBuffersWritePos        ; get current write pos
   mov r17, r16                           ; increment for next call
   inc r17
-  cpi r17, COM_BUFFER_NUM
+  cpi r17, COM_BUFFER_NUM                ; CF set if COM_BUFFER_NUM > R17
   brcs COM_AllocBuffer_l1
   clr r17                                ; wraparound
 COM_AllocBuffer_l1:
@@ -868,8 +961,8 @@ COM_BufferDeallocBack:
   dec r17
   sts comRecvBuffersUsed, r17            ; store new value
   lds r17, comRecvBuffersWritePos
-  tst r17
-  brne COM_BufferDeallocBack_l1
+  tst r17                                ; 0?
+  brne COM_BufferDeallocBack_l1          ; nope go directly decrement r17
   ldi r17, COM_BUFFER_NUM                ; wrap-around
 COM_BufferDeallocBack_l1:
   dec r17
@@ -934,8 +1027,8 @@ COM_BufferDeallocFront_error:
 COM_BufferPosToY:
   ; calculate offset
   clr r17
-  add yl, r16
-  adc yh, r17
+  mov yl, r16
+  clr yh
 
   lsl yl
   rol yh ; *2
diff --git a/avr/timer.asm b/avr/timer.asm
index 2eb86be..ad5b73b 100644
--- a/avr/timer.asm
+++ b/avr/timer.asm
@@ -189,8 +189,9 @@ timerIrq2_l1: ; increment seconds
                       ld r19, x+
                       ld r20, x+
                       ld r21, x
-                      clr r22
-                      inc r18
+                      ldi r22, 1
+                      add r18, r22
+                      dec r22
                       adc r19, r22
                       adc r20, r22
                       adc r21, r22