There is no support for Econet SOCs in OpenWrt so far (yes, they've been bought by Mediatek, but the SOCs have a different heritage and aren't supported yet), so you'd be looking at a steep learning curve.
Everything is 'possible', but only if you have enough time to bring up a new target (and it's questionable if you'll get the xDSL driver source in the first place). Even if you were familiar with this, you'd be looking at 6-9 months development time at best.
Long standing wisdom about Econet has always been "run away".
I work now on H369A, I faced same problem, here is link to the Topic but i was able to extract the firmware from NAND and I got the root files. I may help you if I could of course.
I hope I can add this new platform to OpenWrt one day.