EE technician - I've developed and used custom programmers for embedded microcontrollers I think they reprogrammed the uc that works alongside the radio board to process signals & output text, etc. This wouldn't take long, and it's easy to build programmers that work on multiple units at once 1/

We know the chip isn't locked bc frequency and capcode configuration is one of the AR-924's big features. (Programming port is under the sticker in the top left in older models, Taiwanese model uses USB.) With the manufacturer datasheet, a connection could be made between any suitable pin... 2/