diff --git a/board/main.c b/board/main.c
index 69db9b8ef..8c0f90556 100644
--- a/board/main.c
+++ b/board/main.c
@@ -622,6 +622,9 @@ int usb_cb_control_msg(USB_Setup_TypeDef *setup, uint8_t *resp, int hardwired) {
     case 0xdb: // toggle GMLAN
       set_can2_mode(setup->b.wValue.w);
       break;
+    case 0xdc: // set controls allowed
+      controls_allowed = setup->b.wValue.w == 0x1337;
+      break;
     case 0xe0: // uart read
       ur = get_ring_by_number(setup->b.wValue.w);
       if (!ur) break;
diff --git a/board/panda_safety.h b/board/panda_safety.h
index 029975c56..c6eb36a17 100644
--- a/board/panda_safety.h
+++ b/board/panda_safety.h
@@ -4,10 +4,10 @@ void safety_rx_hook(CAN_FIFOMailBox_TypeDef *to_push) {
 }
 
 int safety_tx_hook(CAN_FIFOMailBox_TypeDef *to_send, int hardwired) {
-  return hardwired;
+  return hardwired && controls_allowed;
 }
 
 int safety_tx_lin_hook(int lin_num, uint8_t *data, int len, int hardwired) {
-  return hardwired;
+  return hardwired && controls_allowed;
 }
 
diff --git a/lib/panda.py b/lib/panda.py
index 3cc1494aa..a9f9e042d 100644
--- a/lib/panda.py
+++ b/lib/panda.py
@@ -105,6 +105,12 @@ class Panda(object):
 
   # ******************* configuration *******************
 
+  def set_controls_allowed(self, on):
+    if on:
+      self.handle.controlWrite(usb1.TYPE_VENDOR | usb1.RECIPIENT_DEVICE, 0xdc, 0x1337, 0, '')
+    else:
+      self.handle.controlWrite(usb1.TYPE_VENDOR | usb1.RECIPIENT_DEVICE, 0xdc, 0, 0, '')
+
   def set_gmlan(self, on):
     if on:
       self.handle.controlWrite(usb1.TYPE_VENDOR | usb1.RECIPIENT_DEVICE, 0xdb, 1, 0, '')
diff --git a/tests/loopback_test.py b/tests/loopback_test.py
index f970c1f16..d279a8aba 100755
--- a/tests/loopback_test.py
+++ b/tests/loopback_test.py
@@ -25,6 +25,9 @@ def run_test():
   h = map(lambda x: Panda(x), pandas)
   print h
 
+  h[0].set_controls_allowed(True)
+  h[1].set_controls_allowed(True)
+
   # test both directions
   for ho in [[0,1], [1,0]]:
 
diff --git a/tests/standalone_test.py b/tests/standalone_test.py
index 0404ee863..fa050314d 100755
--- a/tests/standalone_test.py
+++ b/tests/standalone_test.py
@@ -11,6 +11,7 @@ if __name__ == "__main__":
     p = Panda()
   print p.health()
   print p.get_serial()
+  p.set_controls_allowed(True)
 
   a = 0
   while 1: