The Radioddity GD-77 has a serious bug in firmware version 3.0.6 which causes its transmit power to be set to zero.
This problem normally occurs if the radio performs a Factory Reset because it finds a problem with the codeplug which has been uploaded, but would also occur if the radio is manually reset to its factor settings.
Luckily there is a way to restore valid factory settings.
Note. This does not prevent the problem re-occurring, if a faulty codeplug is uploaded again
Download firmware version 2.6.6 from Radioddity’s website
Unzip the firmware updater. Put the radio into firmware update mode, by turning on with both buttons next to the PTT pressed.
Run the updater and select the .sgl firmware file (which is in the folder above the folder containing the updater.exe
Wait for the updater to complete, and for the radio to reboot
When version 2.6.6 first boots, it checks its internal settings and applies settings which actually work !
Now upgrade back to firmware version 3.0.6
If the Factory Settings were applied because of a problem with the codeplug, Go back to an older version of the codeplug you have saved that does not cause the GD77 to crash and apply factory settings