Couple other things I've tried: disabling virtual memory (no effect), running a DOS program in the foreground (freezes the DOS program after a minute).

Also, it's using APM rather than ACPI for power management.

Edit: tried disabling APM. Didn't work.

I think I know the answer already, but what happens if you try to replicate with a stock (*SE install, not the boutique installer from github?

ldeveraux wrote on 2026-08-31, 17:56:

I think I know the answer already, but what happens if you try to replicate with a stock (*SE install, not the boutique installer from github?

I've been curious to find out, but I already know that a fully stock installation will almost certainly not boot on this machine, at the very least because it has >512MB of RAM, but there are also a bunch of CPU speed related issues that need to be patched. That's why I was using Quickinstall, because it includes those patches by default.

It was already a bit of a bear getting 98SE to make its way through the legacy hardware detection phase anyway. That's skippable in Quickinstall, but it wouldn't boot at all without it.

At this point I don't lose anything from trying a stock install. But I'm 99% sure it will fail in various other ways from the hardlocking, and the hardlocking will probably still be present anyway.

If you're a masochist I suppose you could get the Win98SE DDK and set up WDEB98 and if the serial console debugger doesn't also lock up, poke around at it when it locks up to see what is going on.
edit: oh, I guess no serial port except the tiny chance that an expresscard one might work. but maybe SoftICE instead?

jakethompson1 wrote on 2026-08-31, 18:43:

If you're a masochist I suppose you could get the Win98SE DDK and set up WDEB98 and if the serial console debugger doesn't also lock up, poke around at it when it locks up to see what is going on.
edit: oh, I guess no serial port except the tiny chance that an expresscard one might work. but maybe SoftICE instead?

I suppose that is technically possible. But I get the strong impression that the entire OS has locked up at some low level, like the CPU has just halted entirely.

I'm able to run 98 QuickInstall just fine on a Latitude E6400 and Thinkpad T430, but don't own an X201 to test. On the T430 I get hard freezes if I try to adjust the screen brightness once the OS is loaded and on the E6400 I had a lot of problems with USB until i also added a set of Intel chipset machine.inf files.
If you install without running legacy hardware detection, the latest version of QuickInstall adds 2 serial ports in Device Manager that can have IRQ conflicts with other devices. These should be removed.
I would also try removing the NDIS network drivers if it installed those, both from the Device Manager and DOS startup files.

QuickInstall includes SweetLow's AHCI disk driver. Sometimes AHCI mode works better than legacy IDE and sometimes it's worse depending on the hardware.
If you're using any 16-bit disk drivers there will be a log file in C:\Windows\ios.log about what the IO Subsystem is loading.
You could consider getting a docking station with a serial port to be able to run the Windows Debugger. I'm pretty sure the regular dock has one but the Ultrabase does not.

Dang. I do have the Ultrabase but not the regular dock. I'll look into that.

There are definitely no chipset drivers for this machine. It's a first gen i5 with integrated everything.

I just tried adjusting the screen brightness. Turns out I can reliably make the machine hardlock at will by attempting to do that. Interesting! I wonder what that indicates.

I mean this set of INFs for the chipset devices. https://retrosystemsrevival.blogspot.com/2019 … ers-9x.html?m=1

You could also try Windows Me, sometimes it likes systems better than Win98. Sometimes the reverse is true

Sorry if this has been covered already, but since you mentioned that you likely wouldn't be able to install an unmodified copy of 98se, what if you install vanilla Windows 98SE on a different machine with basically no drivers and then simply copy the working Windows folder over to the X201? Windows 98SE is incredibly flexible in this regard and it would bypass any issues you may run into during the actual install process. As long as there aren't conflicting\incompatible hard drive controller drivers (which there shouldn't be), it should allow you to boot at least and it will tell you if it is a quirk of the Windows version you are installing or something deeper.

If any compatibility patches (memory, CPU, etc) are absolutely required, you can install those before copying things over, but I'd try without them first. Just bare bones Windows with no outside drivers, patches or applications. Add patches as needed to keep things simple.

I will try a stock 98SE install at some point when I have the time, but for now I've done something else that may serve the same purpose:

I tried to install stock Windows 3.1 (WfW 3.11) on my DOS partition.

Result: I can't get past setup, because just like 98SE, it inevitably hardlocks at some point. It literally looks like the CPU is just halting. Just like 98SE it's at a different point in time each time it happens, but it's always within a minute. Nothing in particular seems to trigger it. One time I was almost able to get all the way through setup (in the stage where it builds out Program Manager) before it happened.

And here's something interesting:

One of the times, it happened after I had already exited to DOS and successfully run some commands there. Cursor wouldn't blink, no keyboard input, hardlocked as though the CPU was just completely halted. I haven't encountered that on this machine at the DOS prompt before, and I've been running plenty of protected mode 32 bit software in DOS, like JEMM, SBEMU, DOOM, etc. without encountering this. But running Windows triggered the countdown of doom and even exiting to DOS did not save me. Very interesting!

And before someone says "check your RAM!" I've also been running Linux Mint on this thing with zero issues.