Very quick two cents:

I am not sure about grub2win, but plain grub will boot freedos disk images
perfectly fine.  On my computer, I simply created a fat32 partition, booted
a disk image from grub, and now I run programs off the fat32 partition.
Yes, I have to edit the boot image whenever I want to change my
autoexec/config.sys, but I don't have to worry about the mbr nor messing up
my boot partition.

On Sat, Dec 20, 2025 at 9:20 AM Michał Dec via Freedos-user <
[email protected]> wrote:

> It's not over 4TB, it's for over 2TiB. MBR tables have a 32 bit bitfield
> for addressing sectors - so 0x100000000 (since sector 0 is also
> accounted for) sectors multiplied by 512 bytes per sector, divided by
> 1024^4 bytes per TiB, gives us exactly 2 TiB. GPT introduces 64 bit
> bitfields for sector numbers. Individual devices may also have different
> sector sizes than 512 bytes. There's plenty of HDDs popping up since
> early 2010s that have 4096 bytes per sector, but they support being
> addressed as 512 byte logical sectors for the convenience of whatever is
> trying to access the disk.
>
> W dniu 20.12.2025 o 16:09, Roger via Freedos-user pisze:
> > Clarification, if you're unaware, partition layouts can either be the
> > old MBR (legacy/old DOS) partition layout or GPT newer partition
> > layout, with support for >4TB and required for EFI boot methods.  MBR
> > can only boot old legacy/DOS, no EFI.  GPT can handle both, requiring
> > a workaround for booting MBR related operating systems, however
> > requires BIOS CSM (legacy BIOS support) enabled when booting MBR
> > related operating systems.
> >
> > On Sat, Dec 20, 2025 at 9:42 AM Roger <[email protected]> wrote:
> >> Windows 11 (unlike Windows 10) by default installs to EFI partition.
> >>
> >> I found out the hard way, only use bcdboot.exe for reinstalling the
> >> Microsoft Windows 11 EFI partition and Microsoft Windows 11 relevant
> >> contents into the EFI partition.  If I'm not mistaken, bcdboot will
> >> automatically call the relevant EFI related parts of "bootrec /scanos"
> >> (bootrec.exe), so not needed to run scanos functions.  Trying to use
> >> MBR bootrec.exe executable will cause Windows 11 to not boot, and/or
> >> display the ugly blue repair screen.  (The brief process for deleting
> >> and creating the Windows 11 EFI, remove/create the initial FAT32
> >> partition, boot into the Windows 11 repair, use diskpart for
> >> creating/finding the EFI FAT32 partition and assigning a letter if
> >> needed, exiting from diskpart and running bcdboot incantation for
> >> reinstalling the Windows 11 EFI partition contents. If any other
> >> Windows operating system has been installed via the EFI method (not
> >> MBR method), this process should automatically create a boot menu for
> >> those other Windows EFI bootable operating systems.
> >>
> >> Windows 10 and older operating systems, will call for using
> >> bootrec.exe, working with and install MBR related functions, again,
> >> not compatible with Windows 11.  You'll encounter a lot of
> >> instructions on the Internet directing for utilizing bootrec.exe in
> >> tandem with bcdboot.exe.
> >>
> >> Another hiccup I ran into, likely Windows 10 can be installed via
> >> both, MBR and EFI; or Windows 11 just installs two separate EFI
> >> partitions within one drive, likely for MBR/EFI compatibility.  Weird.
> >> Microsoft only wants and needs you using their latest and greatest
> >> operating system!
> >>
> >> Roger
> >>
> >> On Fri, Dec 19, 2025 at 7:43 PM Tomas By via Freedos-user
> >> <[email protected]> wrote:
> >>> On Sat, 20 Dec 2025 01:31:44 +0100, Karen Lewellen wrote:
> >>>> exactly which Linux?
> >>>
> >>> Well, I only have recent experience with Ubuntu, but it has worked the
> >>> same in all others I have tried, for quite a while now.
> >>>
> >>> /Tomas
> >>>
> >>>
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