Fix multi message iso tp requests

commaai · May 19, 2020 · 5307bf7 · 5307bf7
1 parent 0610ed1
commit 5307bf7
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/python/uds.py b/python/uds.py
@@ -372,15 +372,15 @@ def send(self, dat: bytes) -> None:
     self._tx_first_frame()
 
   def _tx_first_frame(self) -> None:
-    if self.tx_len < 8:
+    if self.tx_len < self.max_len:
       # single frame (send all bytes)
       if self.debug: print("ISO-TP: TX - single frame")
       msg = (bytes([self.tx_len]) + self.tx_dat).ljust(self.max_len, b"\x00")
       self.tx_done = True
     else:
       # first frame (send first 6 bytes)
       if self.debug: print("ISO-TP: TX - first frame")
-      msg = (struct.pack("!H", 0x1000 | self.tx_len) + self.tx_dat[:6]).ljust(self.max_len, b"\x00")
+      msg = (struct.pack("!H", 0x1000 | self.tx_len) + self.tx_dat[:self.max_len - 2]).ljust(self.max_len - 2, b"\x00")
     self._can_client.send([msg])
 
   def recv(self) -> bytes: