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ACPITOOL v1.1 (Announce)

posted by Zyzzle, 04.04.2022, 00:15

> Hello Zyzzle,
>
> > Is it possible to create a UEFI BIOS image with a legacy, generic VGA
> BIOS
> > embedded inside? I would think not since that VGA BIOS would rely on DOS
> > INT calls and contain legacy 16-bit code which won't run in any UEFI
> BIOS?
>
> Actually, I would say yes and no. (!)
>
> My extremely experimental biefircate project
> (https://github.com/tkchia/biefircate) boots up as a UEFI
> bootloader. However, it tries to find a VGA
> option ROM among the
> PC's "Firmware Volumes", and if it does find such an option ROM, it will
> switch to 16-bit real mode, and run the option ROM to put the display in a
> VGA-compatible mode. And yes, this works — on some machines, anyway.
 Thanks for reply, and also for informing of your project. Your inights and tests with using SeaBIOS answer the question; that it is NOT possible for its skeletal VGA BIOS code to be adequate for booting and running DOS applications or games in an UEFI-only, non CSM BIOS system.

I should think the number of UEFI-only systems with any VGA option ROM would be very low, particularly when using onboard video. However, some Chromebooks, older models, probably do have legacy VGA option ROMs. Newer ones, based on upon Intel GeminiLake chipsets, will apparently by design have no legacy option ROMS at all, and crippled by intention. Also, it appears to be true that any systems with onboard Intel Video BIOS have intentionally removed 16-bit option ROM code module support as of 10th or 11th Generation Intel core.

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