Flashing the bootloader
From time to time it will be necessary to flash the bootloader with a newer version.
Copy the currently downloaded firmware (.bin file) into the FIRMWARE directory of the SD card.
Keep in mind that The total number of character in a filename is 32 including the extension file name. So max length is 28 and “.bin” = 4 (dot is considered 1 character).
First you have to jump into the Radio Menu then hit the page button until you get to the SD CARD menu.
Highlight the FIRMWARE directory and press the [Ent] key.
Highlight the bin file and Long Press [Ent].
Choose flash bootloader from the menu and press [Ent].
You can verify the bootloader version by going into the VERSION page of the Radio Menu.