@@ -380,7 +380,7 @@ class LPC:
# If we're writing sector 0, set the checksum
if sector == 0:
iv = struct.unpack('<7I', secdat[0:28])
- cs = struct.pack('<i', -sum(iv))
+ cs = struct.pack('<I', (-(sum(iv) % 2**32)) & 0xFFFFFFFF)
secdat = secdat[:28] + cs + secdat[32:]
# Write data to RAM