Glad it's worked for you
I haven't had any problems since going back to 7C.
This router has been consistently better than all the routers I've tried before - HG12, Draytek 2760, Fritzbox, ZyXel P2812.
To be fair, the P2812HNU was pretty good but sent back about 3 routers because ZyXel's official firmware kept bricking them...hmmm
The 8324 has been solid and I'm leaving it alone now on 7C. I think it has eeked out every last bit on a long copper line and any more attempts on improving speed will decrease stability.