Thanks for the timely reply, that is helpful.
Looking at this particular unit, I realized that the PCB P/N I cited was not correct.
The actual PCB has the P/N EBR65002702. I understand from my parts guide, that this was updated to the replacement part EBR65002703. The page you cited from Service bulletin CNZ201900235-04 only covers EBR7xxx...xx PCBs.
I observed that the FW test port on the EBR65002703 (& the EBER 65002702 as well) has a different pinout than configured in the standard CJT30000002 Firmware update tool. It appears the VCC, Ground, RX and TX ports are there, but they are not in the right order. I'm wondering if I can simply rewire the one of the connectors to match the pinout of the EBR65002703 PCB and whether the update tool will be able to update it. If not, then I'm not sure what the repair strategy will be other than finding an old, new stock OEM compressor that matches the original one. Given that the original fridge was manufactured in 2010, that might prove challenging.
Thus, my first question is can the EBR65002703 board be updated to work with the LG universal compressor? If so, what manufacturing date of the board can be used to do the update?
The second question is if the EBR65002703 board can't be updated to work with the universal compressor, what would be the next best compressor replacement steps or strategy?