The TCNiSO group have released their tutorial on how to implement a modification and hack that enabled a "secret" menu that the developers wrote into the bootloader of this modem. This modification works on RCA 245 and 305 and Thomson 290 modems, it may work on other models too! Once you have enabled the developers menu, you can easily change many of the startup parameters, hardware addresses, firmware, EEPROM as well as a suite of diagnostic tests.