Changing firmware is on your own risk.
Loading Firmware OpenGD77 for Radioddity GD-77. Before doing anything, back up the radio. The firmware currently works with Radioddity GD-77, GD-77S and Beofeng RD-5R. With DM-1801 and RD-5R.
The software can be downloaded here https://github.com/rogerclarkmelbourne/OpenGD77CPS/releases/tag/R2020.10.14 or HERE.
To load the same firmware without installing the programming program - HERE
The menu looks like this:
The radio must be switched on in download mode.
For DM-1801 and GD-77 / s you need to do the following:
The LED is green, the screen is off.
That`s it. Then open the OpenGD77 CPS software and go to the Extras-> Firmware Loader menu
A window will load asking you which radio station to download the Firmware for.
Select the radio station type and click Download & Update. If you have the firmware as a separate file, you can select Select a File & Update.
Then another window appears, allowing you to download the approved versions of the Firmware. We recommend that you select the Stable version.
Click on the version you selected and click Download and Update. After the operation, you can safely turn off the radio and turn it on again. Ready. You already have OpenGD77.
The programmable buttons are now predefined. Here are pictures for Radioddity: