byd: fix SEAL bus topology from live dump — ADAS on bus 0, PCM_BUTTONS confirmed

Live bus dump from the Seal showed a different topology than the Han:
- ACC_HUD_ADAS (813) + ACC_CMD (814) are broadcast on the vehicle CAN
  (bus 0), not the camera CAN. Panda rx check expected 813 on bus 2 and
  never saw it -> safety config invalid -> controls blocked forever.
- PCM_BUTTONS (944) confirmed on bus 0 at 20Hz (MADS button placement OK)
- 482 MPC_LKAS_CMD_ANGLE present on bus 2 (angle LKAS cmd; for future use)

Changes:
- carstate: ADAS messages (ACC_HUD_ADAS/ACC_CMD) read from bus 0 on SEAL,
  bus 2 on HAN (cp_adas accessor); parsers built per platform/bus
- panda byd.h: 813 cruise check is bus-independent; rx checks accept
  813 on bus 0 or 2, 944 on bus 0 or 2 (first-seen-wins)
- interface: disable openpilot longitudinal for SEAL — stock ACC_CMD
  originates on bus 0 where the panda cannot intercept it. Stock ACC +
  MADS lateral it is (which is the point of MADS anyway).
- panda firmware rebuilt

Verified: SEAL (cruise+lkas button via bus 0, alphaLong=False) and
HAN (bus 2 topology, alphaLong=True) both canValid; 120 safety tests +
MISRA clean.

opendbc_repo/opendbc/car/byd/carstate.py

@@ -22,6 +22,10 @@ class CarState(CarStateBase, MadsCarState):
     else:
       self.steer_msg = "STEERING_TORQUE"
 
+    # ADAS cruise state (ACC_HUD_ADAS) and stock ACC echo (ACC_CMD) are on
+    # the vehicle CAN (bus 0) on the SEAL, camera CAN (bus 2) on the HAN
+    self.adas_on_pt_bus = CP.carFingerprint == CAR.BYD_SEAL_PERFORMANCE_25
+
     self.mpc_lkas_cmd_msg = None
     self.eps_steering_torque_msg = None
     self.eps_prepared = False
@@ -35,6 +39,7 @@ class CarState(CarStateBase, MadsCarState):
   def update(self, can_parsers) -> tuple[structs.CarState, structs.CarStateSP]:
     cp = can_parsers[Bus.pt]
     cp_cam = can_parsers[Bus.cam]
+    cp_adas = cp if self.adas_on_pt_bus else cp_cam
     ret = structs.CarState()
     ret_sp = structs.CarStateSP()
 
@@ -59,13 +64,13 @@ class CarState(CarStateBase, MadsCarState):
     ret.steerFaultPermanent = cp.vl[self.steer_msg]["TORQUE_FAILED"] != 0
     ret.steerFaultTemporary = cp.vl[self.steer_msg]["TORQUE_FAILED"] != 0
 
-    ret.stockAeb = cp_cam.vl["ACC_HUD_ADAS"]["AEB"] == 1
-    ret.stockFcw = cp_cam.vl["ACC_HUD_ADAS"]["FCW"] == 1  # Forward Collision Warning
+    ret.stockAeb = cp_adas.vl["ACC_HUD_ADAS"]["AEB"] == 1
+    ret.stockFcw = cp_adas.vl["ACC_HUD_ADAS"]["FCW"] == 1  # Forward Collision Warning
 
     # Cruise state
-    ret.cruiseState.enabled = cp_cam.vl["ACC_HUD_ADAS"]["CRUISE_STATE"] in (3, 5)  # (Active, Override)
-    ret.cruiseState.speed = cp_cam.vl["ACC_HUD_ADAS"]["SET_SPEED"] * 10 * CV.KPH_TO_MS
-    ret.cruiseState.available = cp_cam.vl["ACC_HUD_ADAS"]["CRUISE_STATE"] not in (8, 9)  # (Failure, PermanentFailure)
+    ret.cruiseState.enabled = cp_adas.vl["ACC_HUD_ADAS"]["CRUISE_STATE"] in (3, 5)  # (Active, Override)
+    ret.cruiseState.speed = cp_adas.vl["ACC_HUD_ADAS"]["SET_SPEED"] * 10 * CV.KPH_TO_MS
+    ret.cruiseState.available = cp_adas.vl["ACC_HUD_ADAS"]["CRUISE_STATE"] not in (8, 9)  # (Failure, PermanentFailure)
     ret.cruiseState.standstill = False  # This needs to be false, since we can resume from stop without sending anything special
 
     # Gear
@@ -102,7 +107,7 @@ class CarState(CarStateBase, MadsCarState):
     self.mpc_lkas_active = cp_cam.vl["MPC_LKAS_CMD"]["LKAS_ACTIVE"] != 0
     self.mpc_lkas_request_prepare = cp_cam.vl["MPC_LKAS_CMD"]["LKASPrepare"] != 0
     # for generate ACC_CMD
-    self.acc_cmd_msg = copy.copy(cp_cam.vl["ACC_CMD"])
+    self.acc_cmd_msg = copy.copy(cp_adas.vl["ACC_CMD"])
     return ret, ret_sp
 
   @staticmethod
@@ -123,6 +128,23 @@ class CarState(CarStateBase, MadsCarState):
       ("PCM_BUTTONS", float('nan')),
     ]
 
+    cam_messages = [
+      # stock camera command echoes, only present when stock ADAS is active
+      ("MPC_LKAS_CMD", float('nan')),
+      # SEAL camera also broadcasts an angle-based LKAS command (parsed for future use)
+      ("MPC_LKAS_CMD_ANGLE", float('nan')),
+      # PCM_BUTTONS may be forwarded on the camera bus on some harnesses
+      ("PCM_BUTTONS", float('nan')),
+    ]
+
+    # ADAS cruise state and stock ACC echo: vehicle CAN (bus 0) on the SEAL,
+    # camera CAN (bus 2) on the HAN. Alive-check ACC_HUD_ADAS only on the bus it lives on.
+    adas_messages = [("ACC_HUD_ADAS", 10), ("ACC_CMD", float('nan'))]
+    if CP.carFingerprint == CAR.BYD_SEAL_PERFORMANCE_25:
+      pt_messages.extend(adas_messages)
+    else:
+      cam_messages.extend(adas_messages)
+
     # EPS steering feedback message differs by platform; alive-check only
     # the one this car has, parse the other opportunistically
     if CP.carFingerprint == CAR.BYD_SEAL_PERFORMANCE_25:
@@ -132,15 +154,6 @@ class CarState(CarStateBase, MadsCarState):
       pt_messages.append(("STEERING_TORQUE", 10))
       pt_messages.append(("STEERING_TORQUE_ANGLE", float('nan')))
 
-    cam_messages = [
-      ("ACC_HUD_ADAS", 10),
-      # stock camera command echoes, only present when stock ADAS is active
-      ("MPC_LKAS_CMD", float('nan')),
-      ("ACC_CMD", float('nan')),
-      # PCM_BUTTONS may be forwarded on the camera bus on some harnesses
-      ("PCM_BUTTONS", float('nan')),
-    ]
-
     return {
       Bus.pt: CANParser(DBC[CP.carFingerprint][Bus.pt], pt_messages, CANBUS.main_bus),
       Bus.cam: CANParser(DBC[CP.carFingerprint][Bus.pt], cam_messages, CANBUS.cam_bus),

opendbc_repo/opendbc/car/byd/interface.py

@@ -32,8 +32,11 @@ class CarInterface(CarInterfaceBase):
       CarInterfaceBase.configure_torque_tune(candidate, ret.lateralTuning)
 
     # longitudinal control parameters
-    ret.alphaLongitudinalAvailable = True
-    if alpha_long:
+    # HAN: openpilot long available (ACC_CMD replaced on the tapped camera bus).
+    # SEAL: stock ACC_CMD is broadcast directly on the vehicle CAN (bus 0),
+    # so it cannot be intercepted/replaced by the panda — stock ACC only (MADS).
+    ret.alphaLongitudinalAvailable = candidate != CAR.BYD_SEAL_PERFORMANCE_25
+    if alpha_long and ret.alphaLongitudinalAvailable:
       ret.openpilotLongitudinalControl = True
       ret.startingState = True
       ret.startAccel = 0.1

opendbc_repo/opendbc/safety/modes/byd.h

@@ -65,6 +65,13 @@ static bool byd_tx_hook(const CANPacket_t *msg) {
 }
 
 static void byd_rx_hook(const CANPacket_t *msg) {
+  // ACC_HUD_ADAS: cruise state. Vehicle CAN (bus 0) on SEAL, camera CAN (bus 2) on HAN
+  if (msg->addr == 813U) {
+    // CRUISE_STATE in (3, 5) == (Active, Override)
+    uint8_t cruise_state = (msg->data[5] >> 4U) & 0x0FU;
+    pcm_cruise_check((cruise_state == 3U) || (cruise_state == 5U));
+  }
+
   // Main Bus
   if (msg->bus == 0U) {
     // PEDAL
@@ -101,15 +108,6 @@ static void byd_rx_hook(const CANPacket_t *msg) {
     if (msg->addr == 944U) {
       mads_button_press = GET_BIT(msg, BYD_LKAS_ON_BTN_BIT) ? MADS_BUTTON_PRESSED : MADS_BUTTON_NOT_PRESSED;
     }
-  }
-  // Cam Bus
-  else if (msg->bus == 2U) {
-    // ACC_HUD_ADAS
-    if (msg->addr == 813U) {
-      // CRUISE_STATE in (3, 5) == (Active, Override)
-      uint8_t cruise_state = (msg->data[5] >> 4U) & 0x0FU;
-      pcm_cruise_check((cruise_state == 3U) || (cruise_state == 5U));
-    }
   } else {
   }
 }
@@ -134,8 +132,10 @@ static safety_config byd_init(uint16_t param) {
     {.msg = {{287, 0, 5, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // STEER_MODULE
     {.msg = {{792, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true},              // STEERING_TORQUE (HAN)
              {508, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }}},   // STEERING_TORQUE_ANGLE (SEAL)
-    {.msg = {{944, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // PCM_BUTTONS
-    {.msg = {{813, 2, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // ACC_HUD_ADAS
+    {.msg = {{944, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true},              // PCM_BUTTONS (vehicle CAN)
+             {944, 2, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }}},   // PCM_BUTTONS (camera CAN)
+    {.msg = {{813, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true},              // ACC_HUD_ADAS (SEAL: vehicle CAN)
+             {813, 2, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }}},   // ACC_HUD_ADAS (HAN: camera CAN)
     {.msg = {{307, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // STALKS
     {.msg = {{660, 0, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // METER_CLUSTER
     {.msg = {{790, 2, 8, .ignore_checksum = true, .ignore_counter = true, .ignore_quality_flag = true}, { 0 }, { 0 }}},  // MPC_LKAS_CMD

panda/board/obj/gitversion.h

@@ -1,2 +1,2 @@
 extern const uint8_t gitversion[19];
-const uint8_t gitversion[19] = "DEV-264ebf95-DEBUG";
+const uint8_t gitversion[19] = "DEV-5684dd9d-DEBUG";

panda/board/obj/version

@@ -1 +1 @@
-DEV-264ebf95-DEBUG
+DEV-5684dd9d-DEBUG