I have the HDMI ERR-3C occur fairly regularly. My xs54 is connected via HDMI -> DVI cable into the DVI input on my Sammy HLN467 DLP. If there is a momentary power outage or if someone switches the TV input to Component (antenna/video/DVI are all fine), the ERR-3C message will display and the HDMI/DVI output will not work. Usually, I can correct it by some combination of switching from HDD/DVD, playing a DVD, and switching between DVI and video.
On this set, digital signals into s-video and component are very substandard...this appears to be an issue with the Sammy and not with the xs54 as based on numerous units over the past few years...that being said, the 720p upsampled output to DVI matches very nicely with the Sammy. Since we only have analog cable, which looks better in Video mode than S-Video/DVI on that TV, the HDMI/DVI output is used mainly for prerecorded DVDs.
There are two other issues I experience from time to time.
1. Every so often (weeks to months), it will stop reading in clean DVDs, storebought or otherwise. Once this occurs, all discs fail to load. A simple pulling of the plug and replugging corrects this issue, though it takes a few minutes for the unit to reinitialize...no data gets lost (assuming you are not recording at that moment) and it recovers without issue.
2. On Cox (FL Gulf Coast), both times I reset the unit it took approximately two weeks before TVGOS data appeared. Since the second time, I have not had the data dropoff, but typically only have 2 to 5 days of shows. We keep the 3 hr shutdown enabled to ensure power is off most nights/days for at least 6 - 12 hrs.
Manual recording is available, of course, but the unit is very crippled without TVGOS data since the ease of recording, organizing, etc. are dependent on it. The menu is horribly slow to navigate, but knowing the shortcuts (such as hours/channel jumping) makes it tolerable.
I am debating presently whether or not to get a second xs54 unit for another room. On one hand, we are now quite familiar and are overall very happy with the unit. On the flip side, the TVGOS issues and inability to record HD are shortfalls. That being said, I do not like cable boxes and much prefer being able to choose a DVR unit of my liking, but the tradeoff is not being able to get HD, HD recording, and Cox's integrated guide. Since digital cable would likely result in loss of the TVGOS functionality, straddling these choices is not too likely.
I had hoped by now that Toshiba would have put out a unit which did bridge these gaps, but the 55 doesn't seem a significant enough improvement. OTA reception is also not an option.