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MS-DOS 3.2 boots, but not 6.22 - PC XT/8086

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First post, by perhenden

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MS-DOS 3.2 boots OK on my Amstrad PC1640 (XT/8086).
I'm booting from an CF-card, using XT-IDE.
With MS-DOS 6.22, no output is shown after the bios and "booting drive c".
How is this possible?

My process:
I boot qemu-386 with the CF-card from a new machine, and run the official MS-DOS upgrade, selecting to replace DOS.
Afterwards, it boots as expected in qemu, but hangs on the Amstrad.
I replaced the MBR with the one from DOS 3.2, but that did not change the boot behavior.

I read that MS-DOS 6.22 should be compatible with this machine, i.e. it runs on 8086.
Is it possible that the MS-DOS installer has sensed qemu's 386 cpu and enabled some 386 instructions that the Amstrad fails to execute?

How should I do the install, when all I have is a MS-DOS 3.2 boot floppy and is able to write to the CF-card from my new machine? (Linux with qemu).
I can run the MS-DOS installer, but that leaves me with a CF-card that boots in qemu only, not on the actual machine.

Reply 1 of 1, by perhenden

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Made it work!
What I did was to boot the 3.2 image with qemu and then with 3.2 booted, I installed the DOS 6.22 upgrade from floppy images, selecting vendor=Amstrad in the start of the process.
In other words, when upgrading instead of installing, it worked. Curiously I did not get the option to select vendor=Amstrad during the install, only when upgrading.

What's up with that, what does the vendor selection do?
EDIT: doing the upgrade on a new disk also worked, without selecting vendor.

Does the MS-DOS installer make different choices depending on CPU type?
It seems upgrade picks up on something the installer does not.

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