A few days later, the rep from SimplayHD got back to us with the results, and they're not pretty. Apparently the Toshiba HD-A1's HDMI interface, which provides the highest video quality among the player's outputs, is much more susceptible to errors than any HDMI source should be. Specifically, numerous real-world scenarios can induce the "HDMI error" readout we saw on the Toshiba (always accompanied by a lack of any picture on the TV's screen), which sometimes necessitates either restarting the player completely or disconnecting and reconnecting the HDMI cable, but always interrupts playback. Here's an excerpt:
The executive summary is that the Toshiba player appears to be able to handle only two of the many different allowed TV power-on/active states: 1) when TV is fully on with the HDMI input selected and fully active, 2) when HDMI signals effectively indicate the cable has been physically disconnected. The player goes into the Error state whenever it sees the TV's HDMI port in any other kind of standby or interrupted state, which unfortunately, are states seen in the majority of the TVs on the market.In other words, you could get the error and possibly cause the player to crash by simply powering on the TV after the HD-DVD player, by switching inputs on the TV or on an HDMI switching A/V receiver connected to the TV, or even by powering on another piece of gear connected to the same switcher as the player. Of course, many HDMI displays and switchers operate differently, so they may not cause the error while others do.
It's possible that Toshiba will release a new firmware update for its HD-DVD players, which hopefully will address the issues and make its HDMI input less touchy. Of course, all of these problems are exacerbated by the fact that the player takes a minute or more to even turn on, so recovering from crashes is particularly tedious.
A big thanks to SimplayHD for sharing its test results with us.