diff --git a/python/dfu.py b/python/dfu.py
index 9beba45e5..4394d2502 100644
--- a/python/dfu.py
+++ b/python/dfu.py
@@ -100,11 +100,14 @@ class PandaDFU:
   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))
-    if mcu_type == McuType.H7:
-      return binascii.hexlify(struct.pack("!HHH", uid_base[1] + uid_base[5], uid_base[0] + uid_base[4], uid_base[3])).upper().decode("utf-8")
-    else:
-      return binascii.hexlify(struct.pack("!HHH", uid_base[1] + uid_base[5], uid_base[0] + uid_base[4] + 0xA, uid_base[3])).upper().decode("utf-8")
+    try:
+      uid_base = struct.unpack("H" * 6, bytes.fromhex(st))
+      if mcu_type == McuType.H7:
+        return binascii.hexlify(struct.pack("!HHH", uid_base[1] + uid_base[5], uid_base[0] + uid_base[4], uid_base[3])).upper().decode("utf-8")
+      else:
+        return binascii.hexlify(struct.pack("!HHH", uid_base[1] + uid_base[5], uid_base[0] + uid_base[4] + 0xA, uid_base[3])).upper().decode("utf-8")
+    except struct.error:
+      return None
 
   def get_mcu_type(self) -> McuType:
     return self._mcu_type
diff --git a/python/spi.py b/python/spi.py
index 5be1e56b6..2b086dc2b 100644
--- a/python/spi.py
+++ b/python/spi.py
@@ -402,7 +402,8 @@ class STBootloaderSPIHandle(BaseSTBootloaderHandle):
 
   def get_chip_id(self) -> int:
     r = self._cmd(0x02, read_bytes=3)
-    assert r[0] == 1  # response length - 1
+    if r[0] != 1: # response length - 1
+      raise PandaSpiException("incorrect response length")
     return ((r[1] << 8) + r[2])
 
   def go_cmd(self, address: int) -> None: