This seems to be a very common modem/router in Europe and Australia/NZ. It is not currently supported by OpenWRT, but it seems to use code developed as part of OpenWRT, I can't see that it would be too hard to make it supported.
I note there is some documentation in the old wiki, I have used this info to get much further into the router. I would like to move this page into the new area. However reading the docs on adding new devices there seems to be a general reticence to create "yet more unsupported hardware pages". I feel this attitude should be revisited. Reverse engineering a router is often a combined effort and without a place to put the results of efforts, each person attempting it has to start from scratch.
The SOC is supported, NAND on BCM63xx might be a problem though.
However ADSL/ VDSL or FXS (phone-) support will never be possible and wlan not to an extent you'd want to use (54 MBit/s at most, if at all), neither situation is going to change.
I dislike bumping old topics, but this is the top result on Google so I figured this is the best place. The openwrt hardware page for this device has been deleted. I can access it via the wayback machine, but I'm perplexed as to why this is has happened.