VW Passat 2020 2.0TDI 150HP Bosch MD1CS004 ECU reading & writing working experience:
MD1CS004 on Bench with Foxflash Read ok, write ok, checksum no problem, but it was a hassle, it didn’t want to connect every time.
Sometimes it didn’t find the password so it goes in a loop until it throws a error. Work arround is to go in another car with the same protocol from the VAG Group , for example Audi A4 or VW Caddy, and try from there. Sometimes just disconnect the Benchbox from the main unit and leave it like 2 min.
Also tried with Launch X-prog3 Read ok, ️Write ok️ and it worked every time like a charm. Only problem is that it doesn’t do checksum. So i did checksum manually and wrote it with X-prog3.