There is no retail version of Windows for ARM. It only comes pre-installed on ARM devices, or through some partner channel when you form a business deal to sell ARM devices. Last I saw the current way to get Windows on ARM was by extracting it from an old Windows IoT project build. So it's novel and interesting when someone figures out how to work around all these roadblocks to get Windows working on a consumer ARM SBC.

Especially given Windows NT, back when it was called that, was portable, and supported various RISC processors.

The fact that it runs without hacks or fiddling with drivers?

They seem to be forever trailing far behind Microsoft's system, though. What version are they targetting now, 2003R2? Windows 7?

It would be very interesting to see what happened, though, if a bunch of companies / government organizations would pool their resources to fund ReactOS development, if only to put the screws on Microsoft when negotiating new licenses. Like IBM mainframe customers putting Amdahl swag on their desks when negotiating with IBM salespeople to get a discount.

If they achieve 100% compatibility, there could also be a significant market for a Windows-compatible system that will support device drivers and software written for old versions of Windows. In my last job, we had a number of customers still running Windows XP on SCADA boxes, because they needed to support some piece of hardware whose vendor had either gone out of business or stopped supporting that hardware, so XP was the last version of Windows with drivers available to support that hardware.

One customer in particular still ran MS-DOS on a few machines for similar reasons - the vendor of their SCADA system had gone out of business ... a long time ago, it seems, and they were very reluctant to migrate to something more recent. It was really weird, because as I remember, some of these machines did not run DOS, but some ancient version of QNX running several virtual DOS machines for visualization stuff.

(Okay, I'm rambling. I should lay off the coffee.)

Official Windows for RPi is Windows 10 IoT Core, not Windows 10. ARM Windows 10 license isn't sold separately but bundled to certificated device (like Surface X), but some hackers installs ARM Windows 10 image (that's for certified devices) to RPi without license.

I wouldn't be surprised if the ARM builds don't require a TPM, and they kick the can down the road WRT requiring equivalent functionality on ARM. TPMs are very, very x86. For instance that LPC bus they sit on is almost electrically the 8086 front side bus, just with a tiny state machine in front to serialize it (hence LPC: Low Pin Count 8086 Bus).

There's of course equivalent security processors and domains on pretty much every ARM application soc, but the exact semantics of them (like pretty much everything in the ARM space that's outside of the actual CPU core complexes) is extremely heterogeneous. They might even be running in EL3 on the application cores themselves. Wrangling all of that is probably out of scope for W11 RTM.

That's pretty interesting.

Going off on a tangent here, but thinking of how most of the world ran Windows XP/Windows 7 on cracked versions, would it be possible that following the TPM requirement, someone would write a TPM emulator (or maybe some more clever hack) so that Windows 11 doesn't complain about those stuffs and just install/boot? (disclaimer: I have no idea how TPM works and have never had to use it...)

I got Windows 11 via Windows Update for my Surface Pro 3. I'm pretty sure it only has TPM and not TPM 2.0.

There was a post yesterday about someone installing it on a recent machine and then swapped the drive to an older allegedly "unsupported" old machine and it worked just fine. YMMV.