Well.. Technically, MS-DOS 5 and 6.x can support up to ~4GB per partition, but..
That requires patching certain system files and
might cause compatibility issues with HDD utilities and other OSes.
So yes, in practice, 2GB per partition are the limit.
Also, MS-DOS 5/6 have got trouble with HDD geometry that goes past 8GB.
That's the same limit that the third-party FastDisk (aka 32BDFA) drivers for Windows 3. 1x have got.
But here, the BIOS plays a smaller role. These drivers may to query drive geometry directly from the HDD.
So a fake HDD geometry cannot be set up in BIOS Setup in order to limit capacity.
Edit: If you encounter trouble, you may also give MS-DOS 7 a try (for testing purposes).
It is LBA aware, supports 2TB max, 4GB files and has a much more sophisticated bootloader.
Its bootloader, for example, can find system files that are located in various locations,
including sub directories.
By contrast, in DOS 5/6, they must always be located at a fixed location.
That may cause issues, if, say, a disk defragmenter of another OS was at work.
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