A couple of the earlier updates adjusted the ATSC tuner function in the 811. It is now probably as good as it gets. It may not be as sensitive (where signal strength is an issue) or interpretive (where multi-casting is an issue) as some ATSC tuners, but better than others.
If you are still plagued by 49% signal readings, you either have a weak souce signal or a multi-path problem. You can help both by optimizing your OTA system (i.e., antenna(s), pre-amp, cable, pointing azimuth), but with the former you may just have to wait until the station goes full-power (as in my case for 1 of the 7 DTV channels broadcast in my area).
Personally I've spent dozens of hours messing with 5 different antennas, 3 pre-amps, a new cable run attenuators, and pointing azimuths. I solved my 2 multi-path problems, but my local ABC station is so low power (1,910 watts) with such a short antenna total height that it can't be locked in my area even though I'm less than 10 miles from the station. Nothing that can be done to the 811's software can fix that.