DOS ain't dead

some TSR/patch to modify BIOS/EDD? (Users)

posted by ecm  , Düsseldorf, Germany, 29.04.2026, 20:56

>
> I would like to prove if NT/XP believes in BIOS/EDD values forwarded at boot
> so I'm looking for a way how to hook int13 and modify returned EDD (turned
> out that GRUB4DOS can't do this)- is there some existing code that can be
> reused for this?

You could use an Extension for lDebug targetting my pre-boot loader. It's described some in http://svardos.org/?p=forum&thread=1764705038

fdbplace.eld is the only loader Extension that I created yet. To modify it for your use, you may want to add some way to identify its presence. In the int 13h handler then modify the 13.48 return buffer as you desire.

If you can't assemble or modify the loader and extension I may look into drafting something like this.

---
l

Complete thread:

• Partitioning of 4TB HDD for legacy OSes - RayeR, 27.04.2026, 22:45 (Users)
  • Partitioning of 4TB HDD for legacy OSes - mceric, 28.04.2026, 01:35
    • Partitioning of 4TB HDD for legacy OSes - bretjohn, 28.04.2026, 03:04
      • Partitioning of 4TB HDD for legacy OSes - Laaca, 28.04.2026, 05:08
        • Partitioning of 4TB HDD for legacy OSes - RayeR, 28.04.2026, 17:28
          • Partitioning of 4TB HDD for legacy OSes - Rugxulo, 29.04.2026, 05:23
            • Partitioning of 4TB HDD for legacy OSes - RayeR, 29.04.2026, 20:09
        • Partitioning of 4TB HDD for legacy OSes - bretjohn, 28.04.2026, 17:30
          • Partitioning of 4TB HDD for legacy OSes - Laaca, 28.04.2026, 18:31
            • Partitioning of 4TB HDD for legacy OSes - RayeR, 28.04.2026, 20:31
    • Partitioning of 4TB HDD for legacy OSes - RayeR, 28.04.2026, 17:21
  • Partitioning of 4TB HDD for legacy OSes - Zyzzle, 29.04.2026, 01:39
    • Partitioning of 4TB HDD for legacy OSes - bretjohn, 29.04.2026, 03:39
    • some TSR/patch to modify BIOS/EDD? - RayeR, 29.04.2026, 20:20
      • some TSR/patch to modify BIOS/EDD? - ecm, 29.04.2026, 20:56
        • some TSR/patch to modify BIOS/EDD? - RayeR, 30.04.2026, 17:31
          • some TSR/patch to modify BIOS/EDD? - ecm, 30.04.2026, 20:06
          • some TSR/patch to modify BIOS/EDD? - Laaca, 01.05.2026, 12:24
          • some TSR/patch to modify BIOS/EDD? - RayeR, 04.05.2026, 17:48
            • failed with hybrid MBR under Windows - RayeR, 07.05.2026, 15:40
              • failed with hybrid MBR under Windows - bretjohn, 07.05.2026, 22:36
                • failed with hybrid MBR under Windows - RayeR, 09.05.2026, 18:16
                  • failed with hybrid MBR under Windows - RayeR, 11.05.2026, 07:47
                    • New Idea how to beak 2TB on WinXP-32 - RayeR, 23.05.2026, 13:51