Let's be clear about this (and yes, this is just re-iterating what has already been told about this device):
- mt7628kn SOC, with 8 MB embedded RAM (non-expandable)
- 2 MB flash (the wiki says 1 MB, but based on the firmware size it must be 2 MB)
- OEM firmware is based on VXworks, not linux (so no sources available, blackbox porting would have to start from zero)
OpenWrt's minimum hardware requirements:
- 8 MB flash (4 MB is no longer enough, even for a custom build it's getting extremely hard to get most basic and bare bones functionality going)
- 64 MB RAM (32 MB is kind of working, in a very limited way - 16 MB is not,
<fullstop>- 8 MB,<muahahaha>)
Chances for OpenWrt support, official or otherwise: 0%.