Firmware update
Along with QGC you can flash your Edge with Etcher.
Grab the latest image
Download the latest available image and extract it
Etcher (Windows/MacOSX)
Click Select image and choose the archive file with image

Click Select drive and wait while Etcher initializes your Edge

Waiting...

Finally, there!

Click Flash.
tip
The process will take a few minutes. Please, be patient!
