the ol' Legacy - UEFI 'Prep for Win11' conundrum

Morning!

I've done a fair amount of Googling on the subject so just thought I'd post some findings and failings of the 'Prep for Win11' with converting MBR to GPT nonsense, along with my solution!

So the hardware here is an ASRock B365M Pro4-F motherboard P1.30 with an Intel i5-9400 CPU, two 4GB RAM modules and a Kingston 500GB NVME SSD currently running Windows 10 Pro on an MBR partition. 9th Gen Intel isn't officially supported according to MS but they say it'll still run Win11.

The PC Health Check app initially showed the TPM issue, so enabled TPM (Go into Security tab and enable Intel Platform Trust Technology in BIOS).

Next scan on Health Check app showed that Windows 11 needs Secure Boot. Checked in BIOS and it is already enabled.

Further digging showed that it could be the MBR partition needing to be GPT so went through the MBR2GPT conversion route and that leads to "no boot media, insert boot media etc" messages.

Further Googling suggests Compatibility Support Module being the issue. Disable CSM in the BIOS and you get stuck with it not booting and just looping back into the BIOS.

Disable Secure Boot and that gets you booting back into Windows 10, and a double check in diskpart shows the disk is now GPT.

Now I've fired up the "WhyNotWin11" tool (grab that from MajorGeeks if the github confuses you) and it's green across the board, says Windows 11 is supported on this system. Huzzah!

Trying to install Windows 11 using the Windows 11 Installation Assistant. This wants the PC Health Check app installed again. Installed and it's now showing green across the board just like WhyNotWin11 tool. (Bare in mind Secure Boot was DISABLED in BIOS/UEFI. Seems like it only needs to see that Secure Boot is supported and not that it is actually enabled)

So here I sit, waiting for the Win11 download to complete. Shall see if it installs and boots. If it does then the red herring here is when Health Check App and WhyNotWin11 say that you need Secure Boot.

UPDATE: Success! Windows 11 installed and booted.

STEPS TAKEN: Enable TPM, Convert MBR to GPT, Disable CSM, Disable Secure Boot, boot to Windows 10, and download install Windows 11 Installation Assistant.

Tried to re-enable Secure Boot in BIOS/UEFI but when I do it just loops without booting. Either way I'm in Windows 11 now on the same hardware so that's as close to a win as I can be arsed with. I hope this helps someone, it had me going in circles for a while.