diff --git a/firmware/config/boards/hellen/small-can-board/meta-info-small-can-board.env b/firmware/config/boards/hellen/small-can-board/meta-info-small-can-board.env
index f026155432..6d0da745ca 100644
--- a/firmware/config/boards/hellen/small-can-board/meta-info-small-can-board.env
+++ b/firmware/config/boards/hellen/small-can-board/meta-info-small-can-board.env
@@ -1,5 +1,6 @@
 SHORT_BOARD_NAME=small-can-board
 PROJECT_CPU=ARCH_STM32F4
+# see '*OPENBLT_CAN*' in board.mk for CAN BLT
 USE_OPENBLT=yes
 # reminder that 'only:small-can-board' in commit message is the way to definitely build a specific target!
 SKIP_RATE=50
diff --git a/firmware/config/boards/hellen/small-can-board/prepend.txt b/firmware/config/boards/hellen/small-can-board/prepend.txt
index e977cf5dd4..bad86583a0 100644
--- a/firmware/config/boards/hellen/small-can-board/prepend.txt
+++ b/firmware/config/boards/hellen/small-can-board/prepend.txt
@@ -2,7 +2,8 @@
 
 
 
-
+#define CAN_ECU_SERIAL_RX_ID 0x300100
+#define CAN_ECU_SERIAL_TX_ID 0x300102
 
 #define ts_show_egt false
 #define ts_show_engine_control false
@@ -12,4 +13,4 @@
 
 #define show_small_can_board_presets true
 
-!#define LUA_SCRIPT_SIZE 30000
\ No newline at end of file
+!#define LUA_SCRIPT_SIZE 30000
diff --git a/firmware/console/binary/serial_can.cpp b/firmware/console/binary/serial_can.cpp
index faa0bd8071..7b20fa7e39 100644
--- a/firmware/console/binary/serial_can.cpp
+++ b/firmware/console/binary/serial_can.cpp
@@ -39,8 +39,8 @@ static CanTsListener listener;
 
 int CanStreamerState::sendFrame(const IsoTpFrameHeader & header, const uint8_t *data, int num, can_sysinterval_t timeout) {
 	int dlc = 8; // standard 8 bytes
-	CanTxMessage txmsg(CanCategory::SERIAL, CAN_ECU_SERIAL_TX_ID, dlc, 0, false);
-	
+	CanTxMessage txmsg(CanCategory::SERIAL, CAN_ECU_SERIAL_TX_ID, dlc, /*bus*/0, IS_EXT_RANGE_ID(CAN_ECU_SERIAL_TX_ID));
+
 	// fill the frame data according to the CAN-TP protocol (ISO 15765-2)
 	txmsg[0] = (uint8_t)((header.frameType & 0xf) << 4);
 	int offset, maxNumBytes;
@@ -73,7 +73,7 @@ int CanStreamerState::sendFrame(const IsoTpFrameHeader & header, const uint8_t *
 		// bad frame type
 		return 0;
 	}
-	
+
 	int numBytes = minI(maxNumBytes, num);
 	// copy the contents
 	if (data != nullptr) {
@@ -141,7 +141,7 @@ int CanStreamerState::receiveFrame(CANRxFrame *rxmsg, uint8_t *buf, int num, can
 			memcpy(tmpRxBuf + sizeof(uint16_t), srcBuf, numBytesAvailable);
 		// copy the crc to the end
 		memcpy(tmpRxBuf + sizeof(uint16_t) + numBytesAvailable, crcBuffer, sizeof(crcBuffer));
-		
+
 		// use the reconstructed tmp buffer as a source buffer
 		srcBuf = tmpRxBuf;
 		// we added the 16-bit size & 32-bit crc bytes
@@ -296,7 +296,7 @@ can_msg_t CanStreamerState::streamAddToTxTimeout(size_t *np, const uint8_t *txbu
 		offset += numBytesToAdd;
 		numBytes -= numBytesToAdd;
 	}
-	
+
 	if (engineConfiguration->verboseIsoTp) {
 		PRINT("*** INFO: streamAddToTxTimeout remaining goes to buffer %d" PRINT_EOL, numBytes);
 	}
@@ -318,7 +318,7 @@ can_msg_t CanStreamerState::streamFlushTx(can_sysinterval_t timeout) {
 		//warning(ObdCode::CUSTOM_ERR_CAN_COMMUNICATION, "CAN sendDataTimeout() problems");
 	}
 	txFifoBuf.clear();
-	
+
 	return CAN_MSG_OK;
 }
 
diff --git a/firmware/controllers/can/can.h b/firmware/controllers/can/can.h
index 3c9a19a510..e4a3cae0b5 100644
--- a/firmware/controllers/can/can.h
+++ b/firmware/controllers/can/can.h
@@ -43,6 +43,9 @@ enum class CanInterval : uint16_t {
 	_MAX_Cycle = _1000ms,
 };
 
+// 11 bit (CAN 2.0A)
+#define IS_EXT_RANGE_ID(id) ((id) >= 2048)
+
 class CanListener;
 class CanSensorBase;