I found this: https://github.com/houzhenggang/mt7620_sdk
I was able to extract the source with:
cat source.tar.bz2.part1 source.tar.bz2.part2 > source.tar.bz2 tar xvjf source.tar.bz2
It seems the source code ( Version 184.108.40.206 ) of the linux SDK for the the MediaTek 7620, 7621 and Ralink 3883 3352 5350 3052.
Considering the problems that plague MT7620 (ex: NEXX 3020 (MT7620) Wi-Fi issues Xiaomi MiWifi mini wireless signal question), I wonder if these can help to fix the drivers for the routers that use these chips.
Are these something new?
I know they are for kernel linux-2.6.36.x but can they help?