I've heard from two people who have spent some time and effort trying to run MSDOS on the Sx0. You can read about their efforts here. We have:
Over time Gregg in Idaho has been continuing his battle with the Wyse S30 and trying to turn it into a simple DOS machine which he can use in the first instance to run some old CNC software. This is his story.
In January 2018 he finally got around to trying DOS 7.1. He could boot it from a USB floppy drive, see the IDE module and install DOS to it. However what ever else he tried it refused to boot from the IDE drive claiming that there was no operating system.
Previously he had successfully used an (all-in-french) FreeDOS image that he'd found that somebody had put together for an Sx0 with 64MB of flash. That author had somehow got around the booting-from-IDE problem.
In Sept 2018 he sent the current summary of the situation:
Like I found early on with the Sx0, the prime problem no doubt lies in odd behaviour by the BIOS such as the way it marks the IDE interface as 'disabled' even if it has just booted something from it. My solution with Tiny Core Linux was to patch the IDE driver to re-enable it. I'm sure something similar can be done here - but it does require time and effort (and ideally source code) to patch either the S30 BIOS, the OS boot code or the OS itself.
If you try something and get anywhere please let me know using the link at the bottom of the page.
A few passing thoughts from Gregg:
It would be great to see the FreeDOS installer fixed so it can do what the MS and IBM DOS installers can.
Fixing the BIOS would be very nice. So would figuring out why MS-DOS 6.22 and PC-DOS 2000 have no issues with the IDE to install to it but then can't boot it.
Maybe a 98SE or WinME boot floppy might be able to boot and format c: /s ? Possibly the S30 would then boot off the DOM, since the CDU 7.1 is put together from the DOS 7.1 from those Windows versions.
I'd love to get sound working for DOS then see if DOOM and Duke Nukem 3D will run on one.
I made a 512 meg USB stick that's supposed to boot and install the CD version of 7.1 CDU, but no go on that. Just sits there with blinking cursor. I want to see what the addons do and nobody has come up with the addons floppy disk images. Next step will be to try my USB to 40 pin IDE adapter and power supply with a CD-ROM drive and the 7.1 CDU ISO burned to a disc.
What's on Disc 1 of 7.1 CDU should be enough to get one going for my mill, if the Sx0 upper memory space has a 64K hole somewhere so EMS can be made to work. That's the problem with an old laptop I tried, all the built in peripherals don't leave a large enough unused range for EMS.