diff --git a/board/can_declarations.h b/board/can_declarations.h
index 569e2939ac..878d9c77e2 100644
--- a/board/can_declarations.h
+++ b/board/can_declarations.h
@@ -13,7 +13,7 @@
 #endif
 
 typedef struct {
-  unsigned char reserved : 1;
+  unsigned char fd : 1;
   unsigned char bus : 3;
   unsigned char data_len_code : 4;  // lookup length with dlc_to_len
   unsigned char rejected : 1;
diff --git a/board/drivers/bxcan.h b/board/drivers/bxcan.h
index e4c72c61aa..721a7ee492 100644
--- a/board/drivers/bxcan.h
+++ b/board/drivers/bxcan.h
@@ -89,6 +89,7 @@ void process_can(uint8_t can_number) {
       if ((CANx->TSR & CAN_TSR_RQCP0) == CAN_TSR_RQCP0) {
         if ((CANx->TSR & CAN_TSR_TXOK0) == CAN_TSR_TXOK0) {
           CANPacket_t to_push;
+          to_push.fd = 0U;
           to_push.returned = 1U;
           to_push.rejected = 0U;
           to_push.extended = (CANx->sTxMailBox[0].TIR >> 2) & 0x1U;
@@ -144,6 +145,7 @@ void can_rx(uint8_t can_number) {
     // add to my fifo
     CANPacket_t to_push;
 
+    to_push.fd = 0U;
     to_push.returned = 0U;
     to_push.rejected = 0U;
     to_push.extended = (CANx->sFIFOMailBox[0].RIR >> 2) & 0x1U;
@@ -159,6 +161,7 @@ void can_rx(uint8_t can_number) {
     if (bus_fwd_num != -1) {
       CANPacket_t to_send;
 
+      to_send.fd = 0U;
       to_send.returned = 0U;
       to_send.rejected = 0U;
       to_send.extended = to_push.extended; // TXRQ
diff --git a/board/drivers/can_common.h b/board/drivers/can_common.h
index 5a074e775c..0f24a77c1b 100644
--- a/board/drivers/can_common.h
+++ b/board/drivers/can_common.h
@@ -131,10 +131,10 @@ void can_clear(can_ring *q) {
 // Helpers
 // Panda:       Bus 0=CAN1   Bus 1=CAN2   Bus 2=CAN3
 bus_config_t bus_config[BUS_CONFIG_ARRAY_SIZE] = {
-  { .bus_lookup = 0U, .can_num_lookup = 0U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
-  { .bus_lookup = 1U, .can_num_lookup = 1U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
-  { .bus_lookup = 2U, .can_num_lookup = 2U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
-  { .bus_lookup = 0xFFU, .can_num_lookup = 0xFFU, .forwarding_bus = -1, .can_speed = 333U, .can_data_speed = 333U, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
+  { .bus_lookup = 0U, .can_num_lookup = 0U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_auto = false, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
+  { .bus_lookup = 1U, .can_num_lookup = 1U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_auto = false, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
+  { .bus_lookup = 2U, .can_num_lookup = 2U, .forwarding_bus = -1, .can_speed = 5000U, .can_data_speed = 20000U, .canfd_auto = false, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
+  { .bus_lookup = 0xFFU, .can_num_lookup = 0xFFU, .forwarding_bus = -1, .can_speed = 333U, .can_data_speed = 333U, .canfd_auto = false, .canfd_enabled = false, .brs_enabled = false, .canfd_non_iso = false },
 };
 
 void can_init_all(void) {
@@ -165,7 +165,7 @@ void ignition_can_hook(CANPacket_t *to_push) {
   if (bus == 0) {
     int addr = GET_ADDR(to_push);
     int len = GET_LEN(to_push);
-    
+
     // GM exception
     if ((addr == 0x1F1) && (len == 8)) {
       // SystemPowerMode (2=Run, 3=Crank Request)
diff --git a/board/drivers/can_common_declarations.h b/board/drivers/can_common_declarations.h
index 1a3518c2a8..57bf87d9c7 100644
--- a/board/drivers/can_common_declarations.h
+++ b/board/drivers/can_common_declarations.h
@@ -13,6 +13,7 @@ typedef struct {
   int8_t forwarding_bus;
   uint32_t can_speed;
   uint32_t can_data_speed;
+  bool canfd_auto;
   bool canfd_enabled;
   bool brs_enabled;
   bool canfd_non_iso;
diff --git a/board/drivers/fdcan.h b/board/drivers/fdcan.h
index 0144aa17c2..197d159826 100644
--- a/board/drivers/fdcan.h
+++ b/board/drivers/fdcan.h
@@ -100,7 +100,11 @@ void process_can(uint8_t can_number) {
           fifo = (canfd_fifo *)(TxFIFOSA + (tx_index * FDCAN_TX_FIFO_EL_SIZE));
 
           fifo->header[0] = (to_send.extended << 30) | ((to_send.extended != 0U) ? (to_send.addr) : (to_send.addr << 18));
-          uint32_t canfd_enabled_header = bus_config[can_number].canfd_enabled ? (1UL << 21) : 0UL;
+
+          // If canfd_auto is set, outgoing packets will be automatically sent as CAN FD if an incoming CAN-FD packet was received
+          bool fd = bus_config[can_number].canfd_auto ? bus_config[can_number].canfd_enabled : to_send.fd;
+          uint32_t canfd_enabled_header = fd ? (1UL << 21) : 0UL;
+
           uint32_t brs_enabled_header = bus_config[can_number].brs_enabled ? (1UL << 20) : 0UL;
           fifo->header[1] = (to_send.data_len_code << 16) | canfd_enabled_header | brs_enabled_header;
 
@@ -115,6 +119,7 @@ void process_can(uint8_t can_number) {
           // Send back to USB
           CANPacket_t to_push;
 
+          to_push.fd = fd;
           to_push.returned = 1U;
           to_push.rejected = 0U;
           to_push.extended = to_send.extended;
@@ -168,6 +173,10 @@ void can_rx(uint8_t can_number) {
     // getting address
     fifo = (canfd_fifo *)(RxFIFO0SA + (rx_fifo_idx * FDCAN_RX_FIFO_0_EL_SIZE));
 
+    bool canfd_frame = ((fifo->header[1] >> 21) & 0x1U);
+    bool brs_frame = ((fifo->header[1] >> 20) & 0x1U);
+
+    to_push.fd = canfd_frame;
     to_push.returned = 0U;
     to_push.rejected = 0U;
     to_push.extended = (fifo->header[0] >> 30) & 0x1U;
@@ -175,9 +184,6 @@ void can_rx(uint8_t can_number) {
     to_push.bus = bus_number;
     to_push.data_len_code = ((fifo->header[1] >> 16) & 0xFU);
 
-    bool canfd_frame = ((fifo->header[1] >> 21) & 0x1U);
-    bool brs_frame = ((fifo->header[1] >> 20) & 0x1U);
-
     uint8_t data_len_w = (dlc_to_len[to_push.data_len_code] / 4U);
     data_len_w += ((dlc_to_len[to_push.data_len_code] % 4U) > 0U) ? 1U : 0U;
     for (unsigned int i = 0; i < data_len_w; i++) {
@@ -193,6 +199,7 @@ void can_rx(uint8_t can_number) {
     if (bus_fwd_num != -1) {
       CANPacket_t to_send;
 
+      to_push.fd = to_push.fd;
       to_send.returned = 0U;
       to_send.rejected = 0U;
       to_send.extended = to_push.extended;
diff --git a/board/main_comms.h b/board/main_comms.h
index 7d754d050f..6cc2e429c3 100644
--- a/board/main_comms.h
+++ b/board/main_comms.h
@@ -317,6 +317,10 @@ int comms_control_handler(ControlPacket_t *req, uint8_t *resp) {
     case 0xe7:
       set_power_save_state(req->param1);
       break;
+    // **** 0xe8: set can-fd auto swithing mode
+    case 0xe8:
+        bus_config[req->param1].canfd_auto = req->param2 > 0U;
+        break;
     // **** 0xf1: Clear CAN ring buffer.
     case 0xf1:
       if (req->param1 == 0xFFFFU) {
diff --git a/python/__init__.py b/python/__init__.py
index 14d324ab93..d6d3ebc594 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -31,7 +31,7 @@ def calculate_checksum(data):
     res ^= b
   return res
 
-def pack_can_buffer(arr):
+def pack_can_buffer(arr, fd=False):
   snds = [b'']
   for address, dat, bus in arr:
     assert len(dat) in LEN_TO_DLC
@@ -41,7 +41,7 @@ def pack_can_buffer(arr):
     data_len_code = LEN_TO_DLC[len(dat)]
     header = bytearray(CANPACKET_HEAD_SIZE)
     word_4b = address << 3 | extended << 2
-    header[0] = (data_len_code << 4) | (bus << 1)
+    header[0] = (data_len_code << 4) | (bus << 1) | int(fd)
     header[1] = word_4b & 0xFF
     header[2] = (word_4b >> 8) & 0xFF
     header[3] = (word_4b >> 16) & 0xFF
@@ -807,6 +807,9 @@ def set_can_data_speed_kbps(self, bus, speed):
   def set_canfd_non_iso(self, bus, non_iso):
     self._handle.controlWrite(Panda.REQUEST_OUT, 0xfc, bus, int(non_iso), b'')
 
+  def set_canfd_auto(self, bus, auto):
+      self._handle.controlWrite(Panda.REQUEST_OUT, 0xe8, bus, int(auto), b'')
+
   def set_uart_baud(self, uart, rate):
     self._handle.controlWrite(Panda.REQUEST_OUT, 0xe4, uart, int(rate / 300), b'')
 
@@ -828,15 +831,15 @@ def can_reset_communications(self):
     self._handle.controlWrite(Panda.REQUEST_OUT, 0xc0, 0, 0, b'')
 
   @ensure_can_packet_version
-  def can_send_many(self, arr, timeout=CAN_SEND_TIMEOUT_MS):
-    snds = pack_can_buffer(arr)
+  def can_send_many(self, arr, *, fd=False, timeout=CAN_SEND_TIMEOUT_MS):
+    snds = pack_can_buffer(arr, fd=fd)
     for tx in snds:
       while len(tx) > 0:
         bs = self._handle.bulkWrite(3, tx, timeout=timeout)
         tx = tx[bs:]
 
-  def can_send(self, addr, dat, bus, timeout=CAN_SEND_TIMEOUT_MS):
-    self.can_send_many([[addr, dat, bus]], timeout=timeout)
+  def can_send(self, addr, dat, bus, *, fd=False, timeout=CAN_SEND_TIMEOUT_MS):
+    self.can_send_many([[addr, dat, bus]], fd=fd, timeout=timeout)
 
   @ensure_can_packet_version
   def can_recv(self):
diff --git a/tests/libpanda/libpanda_py.py b/tests/libpanda/libpanda_py.py
index 6f888ac60e..d24640b9dc 100644
--- a/tests/libpanda/libpanda_py.py
+++ b/tests/libpanda/libpanda_py.py
@@ -12,7 +12,7 @@
 
 ffi.cdef("""
 typedef struct {
-  unsigned char reserved : 1;
+  unsigned char fd : 1;
   unsigned char bus : 3;
   unsigned char data_len_code : 4;
   unsigned char rejected : 1;