DOS ain't dead

failed with hybrid MBR under Windows (Users)

posted by RayeR , CZ, 09.05.2026, 18:16

I know that hybrid MBR is some kind of grey zone, just hoped it would work well as under Linux. To precise previous observation about Win7, I found that they probably checks only one Byte of MBR partition entry - the partition type. If I zero this Byte for remaining 3 partition entries (leaving CHS and LBA values in place) then Win7 recognizes valid GPT. So instead of swapping whole MBR it would be enough to just change these 3 Bytes...

Another possible approach:
do you know about some program like OSFMount or ImDisk but that can mount a part of physical disk instead image file? AI halucinated me that it could be possible selecting physical disk in file open menu and entering specific LBA of start partition and size but I didn't see such option - only mounting image files. But technically it is be possible...

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DOS gives me freedom to unlimited HW access.

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