diff --git a/opendbc_repo/opendbc/car/hyundai/carcontroller.py b/opendbc_repo/opendbc/car/hyundai/carcontroller.py
index 5fd126118..660ec5fc1 100644
--- a/opendbc_repo/opendbc/car/hyundai/carcontroller.py
+++ b/opendbc_repo/opendbc/car/hyundai/carcontroller.py
@@ -238,8 +238,9 @@ class CarController(CarControllerBase):
     else:
       # button presses
       if (self.frame - self.last_button_frame) * DT_CTRL > 0.25:
-        # cruise cancel
-        if CC.cruiseControl.cancel:
+        # cruise cancel - suppress when stock ACC is the fallback (ECU disable failed),
+        # so openpilot doesn't fight/cancel the user's stock cruise
+        if CC.cruiseControl.cancel and not self.ecu_disable_failed:
           if self.CP.flags & HyundaiFlags.CANFD_ALT_BUTTONS:
             can_sends.append(hyundaicanfd.create_acc_cancel(self.packer, self.CP, self.CAN, CS.cruise_info))
             self.last_button_frame = self.frame
diff --git a/selfdrive/car/card.py b/selfdrive/car/card.py
index b6f7707c9..54275c608 100644
--- a/selfdrive/car/card.py
+++ b/selfdrive/car/card.py
@@ -301,7 +301,10 @@ class Car:
         for cfg in self.FPCP.safetyConfigs:
           cfg.safetyParam &= ~LONG_FLAG
         # Let stock ACC manage cruise (prevents "controls mismatch" error)
+        # Clear openpilotLongitudinalControl so controlsd doesn't set
+        # cruiseControl.override=True (which fights stock ACC and causes engage flicker)
         self.CP.pcmCruise = True
+        self.CP.openpilotLongitudinalControl = False
         self.params.put("CarParams", self.CP.to_bytes())
         self.params.put("StarPilotCarParams", self.FPCP.to_bytes())
       # signal pandad to switch to car safety mode