Hi Bowden
I personally do not believe it is firmware connected - if it was, it would be widespread and known
We were one of the first in 2010 for fttc, 40/10 was the highest I think we were on, and we are still on the original hg612 (working fine touch wood), with original power adaptor, but I'm aware of the faulting power adaptor later notified.
I personally believe they need wall mounting, for cooling or they have a tendency to fail
I could be wrong so apologies in advance
Many thanks
John