I recently updated an 878UV from 1.21 to 3.02 with no problems.? Be sure you have your codeplug saved where you can find it to load into the new CPS program.? I don't think you'll be able to use firmware 3.03 because it's only for the D878UVII PLUS according to the PDF included in the download:
D878UV --- Please use the firmware D878UV_Vx.xx for updating the radio.
D878UVII --- Please use the firmware D878UVII_Vx.xx for updating the radio.
If you use wrong firmware for updating, the radio will remind “version error”. After load into correct firmware, it will work fine.
