diff --git a/python/__init__.py b/python/__init__.py
index 2e44b3db..59fe2e0d 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -224,7 +224,7 @@ class Panda:
   FLAG_GM_HW_CAM_LONG = 2
 
   def __init__(self, serial: Optional[str] = None, claim: bool = True, disable_checks: bool = True):
-    self._serial = serial
+    self._connect_serial = serial
     self._disable_checks = disable_checks
 
     self._handle = None
@@ -252,9 +252,9 @@ class Panda:
     self._handle = None
 
     # try USB first, then SPI
-    self._handle, serial, self.bootstub, bcd = self.usb_connect(self._serial, claim=claim, wait=wait)
+    self._handle, serial, self.bootstub, bcd = self.usb_connect(self._connect_serial, claim=claim, wait=wait)
     if self._handle is None:
-      self._handle, serial, self.bootstub, bcd = self.spi_connect(self._serial)
+      self._handle, serial, self.bootstub, bcd = self.spi_connect(self._connect_serial)
 
     if self._handle is None:
       raise Exception("failed to connect to panda")
@@ -277,6 +277,7 @@ class Panda:
     self._assume_f4_mcu = (self._bcd_hw_type is None) and missing_hw_type_endpoint
 
     self._serial = serial
+    self._connect_serial = serial
     self._mcu_type = self.get_mcu_type()
     self.health_version, self.can_version, self.can_health_version = self.get_packets_versions()
     logging.debug("connected")
diff --git a/python/dfu.py b/python/dfu.py
index dfdec1fd..86c48839 100644
--- a/python/dfu.py
+++ b/python/dfu.py
@@ -46,7 +46,7 @@ class PandaDFU:
     return dfu_serials
 
   @staticmethod
-  def st_serial_to_dfu_serial(st, mcu_type=McuType.F4):
+  def st_serial_to_dfu_serial(st: str, mcu_type: McuType = McuType.F4):
     if st is None or st == "none":
       return None
     uid_base = struct.unpack("H" * 6, bytes.fromhex(st))
diff --git a/tests/hitl/0_dfu.py b/tests/hitl/0_dfu.py
new file mode 100644
index 00000000..990823ac
--- /dev/null
+++ b/tests/hitl/0_dfu.py
@@ -0,0 +1,21 @@
+from panda import Panda, PandaDFU
+from .helpers import test_all_pandas, panda_connect_and_init
+
+@test_all_pandas
+@panda_connect_and_init
+def test_dfu(p):
+  app_mcu_type = p.get_mcu_type()
+  dfu_serial = PandaDFU.st_serial_to_dfu_serial(p.get_usb_serial(), p.get_mcu_type())
+
+  p.reset(enter_bootstub=True)
+  p.reset(enter_bootloader=True)
+  assert Panda.wait_for_dfu(dfu_serial, timeout=20), "failed to enter DFU"
+
+  dfu = PandaDFU(dfu_serial)
+  assert dfu._mcu_type == app_mcu_type
+
+  assert dfu_serial in PandaDFU.list()
+
+  dfu.clear_status()
+  dfu.reset()
+  p.reconnect()