It will be useful for many beginner users to add information about how to do this backup. For example how to switch GD 77 to access memory mode before use buttons "Backup ...."Backup Before You Do Anything Else
Before writing a codeplug to the radio, you should backup both the EEPROM and Flash chip, and save the files
somewhere safe, in case something goes wrong in the future and you need to restore the data
From: http://members.optuszoo.com.au/jason.re ... 77tune.htm
Your first step should be to take a backup of the entire flash memory and save it to file, so you have a copy to fall back on should something go wrong at some point. Begin by turning the GD-77 off, plug in the programming cable, and turn on the GD-77 while holding down the following key combination: side blue key, green menu button and the * (lock symbol) key. The radio will power up normally with no other unusual visible indication. This can be a tricky key sequence to get right and you might need a few attempts to successfully get this mode started up correctly.
To read the entire flash will take around five and a half minutes. Then Save File and give it a .bin extension, and keep the file somewhere safe. If the file is filled with all 00s then it means the radio didn’t start up in the flash reading mode properly, and you should try the side blue key, green menu button and the * (lock symbol) power up key sequence again.