Microsoft improvements for ARM64 in 24H2

[jeremyd2019]

Started the process to get 24H2 virtual machines (Windows Update hasn't offered it to any of my host machines yet), and noticed a couple of improvements that should make life easier for me:

1. They've got official ISOs now, finally!
2. WinPE now supports x64 emulation as an optional feature that can be added. Wonder if it can run msys2?

Will update as I get further along and see what happens.

[jeremyd2019]

1. the 26100 arm64 winpe doesn't boot under qemu tcg cpu cortex-a76, but does under cortex-a710. I don't think that cpu was an option when I started playing with qemu for this...
2. msys2 does seem to run under the x64 emulation in the arm64 winpe. Tested in qemu tcg running on x86_64 (cause x86_64 emulating arm64 emulating x86_64 makes a lot of sense)

[jeremyd2019]

One funny thing I ran into was deploying the updated Windows Terminal stopped working. It turns out that DISM was erroring out because of the "arm" (not arm64) version of the Xaml dependency being included. I guess when they dropped support for 32-bit arm, they decided to error out instead of just ignoring an unneeded dependency package. Added a tweak to my script to delete the 32-bit arm package if on 24h2 or newer (if I knew off-hand which build dropped 32-bit arm support I could have specified a lower build number, but whatevs).

[jeremyd2019]

Another "improvement" microsoft made is to updates: now a given update can list multiple msu files. When I first looked at KB5046617 on microsoft update catalog I got sticker shock at the size listed, but it turns out that was the size of both update files, and the prerequisite msu (KB5043080) was already included in the version of Windows 11 24H2 on the official iso download, so I could omit that one.

[jeremyd2019]

There seems like there may be an issue with the hyperv drivers in 24H2 - the "Assigned Memory" of the VM is not going down after start like it does with 22H2/23H2.

[jeremyd2019]

1. the 26100 arm64 winpe doesn't boot under qemu tcg cpu cortex-a76, but does under cortex-a710. I don't think that cpu was an option when I started playing with qemu for this...

This isn't related to the virtual cpu. It seems to be intermittent, like there's a timing thing going on, but I've just discovered that removing virtualization=true seems to make it go away.

[jeremyd2019]

Since winpe isn't supposed to be redistributable, I made a github workflow to demonstrate how to make a winpe iso with the virtio drivers, x64 support, and optionally lcu updates in https://github.com/jeremyd2019/winpebuilder/blob/main/.github/workflows/build.yml