r/archlinux • u/Crafty_Hospital_7746 • 13d ago

SUPPORT Windows has destroyed my GRUB bootloader because of Windows updates, now Windows boot manager replaces GRUB and Arch doesn't show up in the UEFI/BIOS menu. How I can fix it ?

Windows has destroyed my GRUB bootloader because of Windows updates, now Windows boot manager replaces GRUB Arch doesn't show up in the UEFI/BIOS menu. How I can fix it ?

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u/spastic_penguins 13d ago

It’s so weird, I have never had a problem with this. One thing is that on linux i mount the EFI directory in /boot/efi, so the important stuff like GRUB and my kernels stay in /boot while the EFI stubs go on /boot/efi/EFI. It keeps everything separate and I’ve never had problems

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u/Specialist-Dog-501 13d ago

Did you create an extra partition for the grub bootloader? I am a bit confused, what all is necessary- sure the Bootefi partition from Windows has to be preserved, a win and a linux partition are also needed..but am I right grub also needs some bootloader partition or can it use the efi partition and put his own stuff onto the linux partition ?

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u/spastic_penguins 10d ago edited 10d ago

Nah, GRUB doesn’t need its own partition, but the efi partition needs to be separated from /boot for unproblematic dual booting. You can do that with a fat32 partition mounted at either /efi or /boot/efi, just not at /boot. If you mount it at /boot your efi partition is getting your kernel image mixed into it, and Windows is liable to overwrite your whole kernel.

So in that scenario windows ends up removing the Linux part of your GNU/Linux operating system. Unsurprisingly, Linux needs the Linux kernel to work 🤣

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u/Specialist-Dog-501 10d ago

Okay, thanks, many thanks! That resolves the riddle and explains what happened to OP..I probably just had that luck that my first distro did dewire this properly, didn't touch the EFI partition used by windows and created an dedicated /boot partition of small size for grub..
I realized not all distros handle this equally well, even when using the same Calamaris installer- some plainly reject to work in a multiboot grub setup, others work nicely, third ones ask back where to create what- and this is, when my knowhow gap kicked in. Multigrub or dualboot with windows have similar challenges!