perhaps you have to recalc eep data with papuas or try to write a proper eeprom of a working c75. you can find this on the board here, or can rip from a full flash if you know the address.
if you already downloaded a full flash into it maybe you forgot to use the otp imei or proper patch (if any).
or, eventually, it can be problem of different hardware, but the amount of _useless_ work put into these craps does not make it probable.
