My GEE2 is currently running on version OPM1.190831.007, and I can't find a way to get a more recent version running. I've tried the flashing tool and manual flashing, but both methods came with their own issues. I'll give them below:
Flashing tool: I get either a 'device already in use' connection error or the device is offline. This besides the more common message that the flashing tool has some problems on windows sometimes, and that I should try refreshing the webpage.
Manual flashing: once I have given the adb reboot-bootloader command, the fastboot devices command won't recognize the device (listed as ???????? instead of the device name/number) or it will be offline. As a result, the commands that should be given afterwards according to the Readme file don't work.
I have the adb debugger from the Android Studio SDK platform-tools folder, so I updated the driver software of the GEE2 with the use of that folder initially. Afterwards I tried installing other adb software as well but that didn't help either.
I have also tried a couple of the simpler solutions, as unplugging and plugging, refreshing the site, using another computer, using another internet browser, deinstallation of the driver software, a factory reset of the GEE2, installing less recent firmware instead of the latest. None of these things changed the outcome.
Any suggestions would be highly appreciated!
Firstly, check if you have enabled developer options on EE2.
I had a hard time flashing it on Windows due to driver issues. My Android studio or ADB had no problem deploying apps to EE2, but the fastboot never worked. I ended up flashing it on a Mac using brew installed adb.