OpenGD77

Amateur radio firmware for the GD-77, GD-77S, DM-1801, DM-1801A, RD-5R, MD-9600/RT-90, MD-UV380/RT-3S, DM-1701/RT-84 and MD2017/RT-82 radios
https://www.opengd77.com/

rt3s

https://www.opengd77.com/viewtopic.php?f=10&t=2548