I made the updates I plan, it is available for testing in first post, as usual.
diebuche, I looked at the vbios you've sent. I think you're right, it might be some mode, but I could not make any sense of it. Also, I'm not sure if it directly concerns our matter. First, because it looks like a lonely 800x600 mode, with no other 1024x768 (the default mode) or 1280x1024 modes around. And also because if you look a few lines after the 0x9EF7 modeline, there is a bunch of 16/9 HD modes, from 420p to 1080p. And these mode are not related to TV, since the TV VESA table is at offset 0x7c7b. So maybe its related to h264 hardware acceleration, or a non VESA way of dealing with HDMI TVs. Finally, both of the strings you found are close to "SPQR" strings, do you know what SPQR stands for (apart from the roman thing) ?