Looks like my HG633 was upgraded to V2.0 firmware last night.
My downstream (to the router) and throughput have both dropped by around 25%.
The downstream SNR has dropped from around 9 (so was being restricted to the 40 Mbps download) and it is now showing between 4 and 5 - struggling, and failing to reach 40 Mbps downstream. Upstream seems uneffected.
I also notice that the line has changed from VDSL2 with vectoring to VDSL2 without vectoring. Why would V2.0 cause this ?
Less than impressed. Is anything likely to improve over time ?
EDIT -
Switched off for 30+ minutes. Rebooting was taking forever so I swapped back to my old HG635.
Downstream inproved +8 Mbps. Throughput was also around +8 Mbps back to the 40 Mbps mark and consequentally my downstream SNR went +3 Db back to nearly 8 Db.
Interleaving is now off again and Vectoring is back on.
I'm still using V1.06t firmware on the HG635.
EDIT 2– 15:10
Potentially worse news.
I swapped back to the HG633 with V2.0 firmware. All lights went green fairly quickly but the Internet light never illuminated (not even red). Left it “running” then after about 15 minutes the broadband light (which had been green) went out.
Looking horribly like that update may have bricked the HG633.
Back to the HG635 again, but I seem to have lost vectoring this time so am running a bit slower, but at least I am running.