I am comfortable with command-line linux, ssh, etc. and as an OpenWrt newbie emboldened by my first successful installation on a Netgear router, I decided to do something really reckless and try flashing my Devolo Magic 2 WiFi adapters.
Of course I half-bricked one of them: the powerline capability is completely gone.
To be fair, the writing was on the wall. This page says "Powerline only supported by external package feed", which unhelpfully points to a dead link. However, and this is what convinced me to take the leap, I found a git commit which instead suggests that "PLC configuration/link should remain in different memory and should work straight forward after flashing" and "pairing should be possible" by playing with GPIO switches.
Buyer beware: none of that is actually true.
In fact, the PLC configuration/link died a horrible death, and of these advertised GPIO switches:
GPIO Switch: 11-PLC Pairing (Active Low) 13-PLC Enable 21-WLAN pow
only 13 and 21 are actually there, and they do bugger all (I tried all possible 4 combinations).
At that point, I tried installing the latest OpenWrt snapshot and that's when GPIO 11 (PLC Pairing) showed up. I was very excited. But unfortunately, it does absolutely nothing at all (I tried both states in case "Active Low" was true). There is no way to pair this adaptor to another one which uses the original firmware.
Last, while I was already morally prepared to kissing goodbye to this powerline adaptor, I tried restoring the original firmware (both via TFTP and by following this guide) with disastrous results. I suspect that the current OEM firmware binary is in fact a bundle of many files and I should decompose and isolate the actual firmware hidden in there.
I am about to bin the adapter and call it a failed experiment, unless you experts have any ideas on how to fix some or all of this. Even going back to the original firmware would be a great achievement.
Thank you in advance for your replies!!