No need for some shady unofficial firmware updating from the AVS Forums, Toshiba has officially released details of the HD DVD 2.0 firmware on their site, which you can get via the ethernet port on the back of the HD-XA1 -A1, and -D1 models. As
somewhat mentioned previously, extended support for Dolby True HD (5.1 channels), "cookie" support, and bandwidth shaping preferences are now available in the firmware. Of course, some of these features will become more useful in the future as new software and hardware are released that take advantage of them.
On the fix side, HDMI support is improved, as well as issues with pixelation, block noise, and audio dropouts (and people say Blu-ray has problems! ...just kidding) It also should eliminate possible high-frequency noise from your monitor when using HDMI connections. So if you're looking for new features, or to eliminate some problems, grab this firmware via the ethernet jack -- or, if you're without 'net connect -- by giving Toshiba a call and requesting a mailed copy of the firmware.
[Thanks again to Michael Rou]