Hi,
I tried today to start your firmware on 800M(bmminer880) the temperature sensor on the third Board stopped working, gave an error. As the temperature jumped to 88, 103 degrees, like lags. I'm stopping at 750M. Before that, a few days I tested 725M.
What about your meter?
What is the power consumption board for 800M and 8.8v?
And what about the setup for each board? I noticed (as I said before) some boards are able to take a good overclocking, some are not. For example, one board can take 700M only, the other 750M.