>end up with UEFI > NT6 bootloader > Windows or Linux

I don't see any advantage to involving Microsoft in the boot process.

>paying attention to the built-in NT6 bootmenu

UEFI firmware vendors provide a boot manager (the UI) for choosing what installed OS to boot. Apple has offered a graphical boot manager (option key at the boot chime) since forever.

NT6 isn't free or open source software so I don't see the various Linux projects wanting NT6 involved at all, in either the single or dual boot use case.

But in effect you're proposing different boot paths, and different UI/UX depending on whether the system is Linux-only or dual boot Windows Linux.

>This deficiency was not a factor before UEFI struck

I can't tell what deficiency you think UEFI has that BIOS didn't have. But maybe you don't like specs? Or are you referring to the much latter added UEFI Secure Boot?

>No matter what, there's not supposed to be any need for a shim.

You seem to think Microsoft wants to be in the business of executing arbitrary and unsigned code, despite all efforts proving the opposite.

>I don't see any advantage to involving Microsoft in the boot process.

Good point. Me neither, never have,

But if they're already there within the PC in some way or another, ideally they should gracefully be able to accomodate Linux under UEFI as easily as it still works when using BIOS.

>in effect you're proposing different boot paths, and different UI/UX depending on whether the system is Linux-only or dual boot Windows Linux.

Not proposing. Been living it for decades. It's only broken under UEFI.

Even on my average pure Windows machine, I normally have about 4 distinct boot paths for each OS using various instances of the NT6 bootloader. Not counting the option of whipping up an emergency boot floppy which can still be made for modern Windows use if all else failed.

Experience has shown, the more viable boot paths, and the fewer obstacles, the greater reliability.

>You seem to think Microsoft wants to be in the business of executing arbitrary and unsigned code

Nope, that's just how they started out and ended up outgrowing IBM. I remember it well, those days are long over.

Likewise, there should never have been any need for Linux to involve any Microsoft code or signing, like SecureBoot, in order to perform on the most secure new PC's without requiring any different default UEFI settings than Windows.