Hi DieBuche, I have successfully updated my vbios using your guide and I really appreciate your knowledge and guide. I now have unsquased apple logo with correct resolution. But I still see black border around chameleon/apple boot screen (around all corners, about 1 inch thick). I know its under scanning issue, But I just dont know how to fix it, and you seems to me the most knowledgeble person on this. But this black border only appears if I am using DVI input and NOT on VGA. I have tried different monitors with1080p resolution, but issue remains the same, so its not a monitor issue. Once windows/mac has booted up I get get perfect resolution of 1080p. I am using ATI 5750. I have added the resolution in apple.com.plist and modified theme. ATI CCC only hepls scaliing/underscanning/overscaaning issue when syatem has booted up. It does not correct it on initial boot i.e. bios splash screen/ apple grey screen/windows safe mod when the gpu driver has not loaded.
I would really apprecaite your help on this.
Thanks to dublove i was finally able to hard flash my MSi ATi HD 5870, i can get now 1920 x 1080, but i still have those 1 inch thick, awful borders. Does anyone know, how to remove them?
I also have this issue with my Radeon 6970.
I have the same problem, with an HD 4850. I noticed the resolution did change, because during boot there were some lines that wouldn't fit in one line and now it does.
Besides, in case of any problem with my monitor, I believe it would be safer to have 800x600 mode. I guess it'd be better to replace another "less useful" resolution, perhaps 1152x864. How can I do that?
Edit: another reason, look what happened to my BIOS screen (previously, it was
fullscreen, almost full, with the same black borders).
Edit2: I managed to replace 1600x1200 with 1920x1080, so BIOS went back to normal, but I still have those borders.
Went to the effort of patching the VBIOS and Chimera now displays in 1920x1080 however it is surrounded by black borders, this is underscan.
So yes, it seems the video adapter is outputting 1080p like you have told it to with the VBIOS edit and your .plist, however it's also taking and scaling down that display resolution. For example, if I install a fresh Catalyst Control in Windows I also get this underscan after the first reboot, you have to go into the CCC scaling options to change it. However this does not work for boot.
Maybe there is something in the Chameleon/Chimera source that references the default underscan? Or else maybe there are some bytes we can edit in the VBIOS to set/clear the default underscan?
I'm not sure if it's relevant but the issue seems to exist on Linux distro's and has been solved there. The Arch Linux Wiki refers to it:
My TV is showing a black border around the screen
When I connected my TV to my Radeon HD 5770 using the HDMI port, the TV showed a blurry picture with a 2-3cm border around it. This is not the case when using the proprietary driver. However, this protection against overscanning (see Wikipedia:Overscan) can be turned off using xrandr:
xrandr --output HDMI-0 --set underscan off
I know it's only cosmetic and we only see the bootloader for a second, but I'd love to get this right after putting so much time into it.