What cable do you have exactly? To disable the immo you need to read out the eeprom, I think there are 2 or 3 on this site that will work with a ft232rl based cable. You can also use a chip burner to read out the eeprom by using a chip clip or unsolder the chip and dump it directly. After you get the read you can flip a few bits to switch off the immo, you have the immo status on is set as 1 and off is set as 2, you need to do the backup page as well. Update the checksum blocks by removing 1 from the existing values and you are good to write back the eeprom.