diff --git a/avr/att84_base.asm b/avr/att84_base.asm
index dc1382b..0a02933 100644
--- a/avr/att84_base.asm
+++ b/avr/att84_base.asm
@@ -40,7 +40,12 @@
 
 
 ; ---------------------------------------------------------------------------
-; list of modules to use
+; firmware settings including list of modules used
+
+#define FW_TYPE AQHOME_FW_TYPE_ATT84_BASE
+#define FW_MAIN_VERSION_HIGH 0
+#define FW_MAIN_VERSION_LOW  1
+
 
 #define BASE_SYSTEM
 #define WITH_FLASH
@@ -53,6 +58,27 @@
 ; #define MODULES_SI7021
 
 
+.set MODULES_MASK = 0
+#ifdef MODULES_TIMER
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_TIMER)
+#endif
+#ifdef MODULES_COM
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_COM)
+#endif
+#ifdef MODULES_LED
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_LED)
+#endif
+#ifdef MODULES_TWI_MASTER
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_TWIMASTER)
+#endif
+#ifdef MODULES_LCD
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_LCD)
+#endif
+#ifdef MODULES_SI7021
+.set MODULES_MASK = MODULES_MASK | (1<<AQHOME_FW_MODULE_SI7021)
+#endif
+
+
 
 ; ---------------------------------------------------------------------------
 ; EEPROM positions
@@ -183,6 +209,7 @@
 .include "com.asm"
 .include "comproto.asm"
 .include "flash.asm"
+.include "flashproto.asm"
 
 
 
diff --git a/avr/comproto.asm b/avr/comproto.asm
index 8d24c4e..9178f73 100644
--- a/avr/comproto.asm
+++ b/avr/comproto.asm
@@ -43,16 +43,6 @@
 .equ CPRO_PACKET_CLAIMADDR_OFFS_ADDRESS = COM_MSG_OFFS_PAYLOAD+4
 .equ CPRO_PACKET_DENYADDR_OFFS_ADDRESS  = COM_MSG_OFFS_PAYLOAD+4
 
-.equ CPRO_PACKET_FLASH_START_OFFS_MSGNUM = COM_MSG_OFFS_PAYLOAD+0 ; 2 bytes
-.equ CPRO_PACKET_FLASH_START_OFFS_ADDR   = COM_MSG_OFFS_PAYLOAD+2 ; 2 bytes
-
-.equ CPRO_PACKET_FLASH_ADDR_OFFS_MSGNUM  = COM_MSG_OFFS_PAYLOAD+0 ; 2 bytes
-.equ CPRO_PACKET_FLASH_ADDR_OFFS_ADDR    = COM_MSG_OFFS_PAYLOAD+2 ; 2 bytes
-
-.equ CPRO_PACKET_FLASH_DATA_OFFS_MSGNUM  = COM_MSG_OFFS_PAYLOAD+0 ; 2 bytes
-.equ CPRO_PACKET_FLASH_DATA_OFFS_ADDR    = COM_MSG_OFFS_PAYLOAD+2 ; 2 bytes
-.equ CPRO_PACKET_FLASH_DATA_OFFS_DATA    = COM_MSG_OFFS_PAYLOAD+4 ; 2 bytes
-
 
 .equ CPRO_WAITTIME_GETADDR       = 130
 .equ CPRO_WAITTIME_CLAIMADDR     = 17
@@ -322,7 +312,7 @@ CPRO_EnqueueComRecvStats:
         st X+, r16
         lds r16, comStatsRecvErrs+1
         st X+, r16
-        lds r16, comStatsHandled               ; 10: ignored
+        lds r16, comStatsHandled               ; 10: handled
         st X+, r16
         lds r16, comStatsHandled+1
         st X+, r16
@@ -454,6 +444,8 @@ CPRO_EnqueueDebug_error:
 #endif
 
 
+
+#ifndef BASE_SYSTEM
 ; ---------------------------------------------------------------------------
 ; Enqueue a DEVICE packet.
 ;
@@ -494,12 +486,13 @@ CPRO_EnqueueDevice:
   ; mark buffer as enqueued with PRIO "normal" (slightly limited number of retries)
   ldi r20, COM_BUFFER_PRIO_NORMAL
   rcall COM_EnqueuePacket      ; (R15, R16)
-  brcc CPRO_EnqueueValue_error
+  brcc CPRO_EnqueueDevice_error
   sec
   ret
 CPRO_EnqueueDevice_error:
   clc
   ret
+#endif
 
 
 
@@ -813,51 +806,4 @@ cproCalcPayloadSize_l2:
 
 
 
-#ifdef WITH_FLASH
-; ---------------------------------------------------------------------------
-; Enqueue a FLASHDATA_ACK packet.
-;
-; IN:
-; - R16: destination address
-; - R17: ACK(1) or NAK(0)
-; - R19:R18: msg num
-; OUT:
-; - CFLAG: set if okay, clear otherwise
-; MODIFIED REGS: R6, R7, R8, R9, R10, R11, R12, R16, R17, X, Y (R3, R4, R15, R16, R17, R18, R19, R20, R21)
-
-CPRO_EnqueueFlashRsp:
-  mov r6, r16
-  mov r7, r17
-  mov r8, r18
-  mov r9, r19
-
-  rcall COM_AllocBufferAndGetXY ; (r16, r17, r21)
-  brcc CPRO_EnqueueFlashRsp_error
-
-  push xh
-    push xl
-      mov r16, r6
-      ldi r17, CPRO_PAYLOAD_FLAGS_SECONDS | (3<<CPRO_PAYLOAD_FLAGS_SHIFT_NUM)
-      ldi r18, CPRO_CMD_FLASH_RSP
-      rcall cproBeginMsgWithVariablePayload  ; (R3, R4, R16, R17, R18, R19, R20, R21, X)
-      st X+, r8                              ; 4: msg num (low)
-      st X+, r9                              ; 5: msg num (high)
-      st X+, r7                              ; 6: ACK or NAK
-    pop xl
-  pop xh
-  rcall cproCalcAndAddChecksumByte
-
-  ; mark buffer as enqueued with PRIO "important" (higher number of retries)
-  ldi r20, COM_BUFFER_PRIO_IMPORTANT
-  rcall COM_EnqueuePacket      ; (R15, R16)
-  brcc CPRO_EnqueueFlashRsp_error
-  sec
-  ret
-CPRO_EnqueueFlashRsp_error:
-  clc
-  ret
-#endif
-
-
-
 
diff --git a/avr/defs.asm b/avr/defs.asm
index 9cbf130..e34c781 100644
--- a/avr/defs.asm
+++ b/avr/defs.asm
@@ -14,5 +14,10 @@
 .equ AQHOME_FW_MODULE_SI7021    = 6
 
 
+.equ AQHOME_FW_TYPE_ATT84_BASE  = 0
 .equ AQHOME_FW_TYPE_ATT84_TEMP1 = 1
 
+
+.equ AQHOME_FW_START_ADDRESS_MAIN = 0x0500
+
+