linuxmemes

Even if that's the case, that's a Windows bug and has nothing to do with UEFI.

Absolutely, no doubt there.

But it's not a bug, it's a feature in their mind. They don't consider that a user might want or have the need to dual boot, "we have WSL for that". So, no attempt will be made to fix this "bug".

Plus UEFI can do all sorts of spying, since the firmware actually knows what you're booting, and thus, I generally tend to avoid UEFI installs. Sure, sometimes there is no choice (no CSM in firmware), but hey, at least I tried 🤷.

Although, I'm pretty sure if Windows touched boot loader in an MBR setup, it surely would remove grub completely.

Not completely, but remove the MBR magic, yes.

But it doesn't do that. Why mess with something that can render the OS completely unbootable... I presume that's their POV... plus, there is nothing really to do in MBR regarding the magic, things rarely get updated regarding that (I still haven't seen any KBs regarding MBR) and they pretty much have given up on that boot method (which doesn't mean it's not present in the installer and the OS for compatibility reasons in mixed scenarios - GPT partitions, but the disk still holds the MBR magic, just in case the firmware somehow gets reset and CSM is the default boot method, not UEFI), so... yeah, they don't give much attention to it. It's just there and that's all. Hence why they don't actually check whether their MBR magic is present on the disk or not.

In UEFI, it can just don't touch Grub's stuff easily; if it doesn't then that's its problem.

Actually, it's my (our) problem, since they don't see the need to dual boot and they don't treat this as a bug. I'm left to deal with the dual boot UEFI peoblem. So, in order to ensure my dual boot setup always works, I don't use UEFI boot, I use MBR boot 🤷.

MBR simplicity is a lie! It is simple itself, but boot loaders are complex: Grub effectively has 3 separate stages (1, 1.5 & 2) to just run itself...

No doubt there, but it's the MBR magic that starts the chain. It is that, and only that part, which Windows needs (and GRUB as well) to start booting the rest of the bootloader and everything else. It never checks if that is present or OK, because the assumption is, if it can boot, it surely must work as expected, so it never does that check. Defender doesn't even scan MBR any more (older versions in Win7 and Vista did, but newer ones don't), so everything just works with dual boot and MBR boot 🤷.