@Astx
If you read from Post #33 onwards, it seems that FirmwareUpdateforGTMxxDigitalRadioTypeS_230.gcd is safe [the first file in Post #1]. You can also use the file attached in SavaSoo's Post #33 which he reported identifying as V2.20 on the unit however those two files are identical. Usage of any other files linked or attached in this thread has either resulted in a bricked GTM70 or has not been tested. Use at your own risk.