linuxmemes

Windows only in a VM.

I dual boot grub+linux from a wholly separate drive set as the boot drive, windows boot loader is unused, untouched, isolated on the windows drive.

Windows update still broke grub.

Pull my hair out for a few hours trying to find a fix, about to try something but have to reboot one last time.

Everything is fine, back to normal.

Windows is the virus

I've been dualbooting for over a year now. Made sure each system has its own separate drive. I've noticed that every time I had to reinstall Linux, my windows boot entry is gone and then I can't access it no matter what I tried. Turned out installing Linux first then windows was my mistake. When installing windows while there is a Linux install, windows will see the EFI partition already there and just decides to share it, and doesn't create its own.

I found that out by accident while I was in windows' storage management. There was no efi partition. Took a whole day to find out how to create one on the same drive where windows is installed and removing the one it created on the Linux partition. It was so painful.

Bottomline, install windows first if you want to dualboot. After that, even if windows takes over the boot after an update, all it does is resets the boot sequence and makes it default to it. You'd just need to access the bios and reset the sequence to prioritize Linux. That's it

Just stop dual booting. This is self-inflicted harm. Setup a VM or find a native workaround.

I know this one weird trick to avoid this..

I actually had a Linux update do this once when it updated grub. Took a bit to fix but nothing was lost.

Easily solved. Just run mkfs_ext4 on the windows partition, and mount it as an additional filesystem.

My windows ssd died about 2 weeks ago, but I was dual booting.

Took out the windows drive, slapped in a new one and I was no longer getting failed smart checks.

Happy to say that the windows drive that died was replaced with a new 990… that’ll be more storage for my Fedora Plasma system instead of getting windows 10 reinstalled. Win 11 was never a consideration but I did want to keep 10 around for as long as I could.

c'est la vie

I'll do you one better. Do you know what a windows update killed on my multi boot system? It killed the windows bootloader. I'm working on a permanent solution to fixing this bootloader fudgery.

Pre-UEFI they were fighting over the boot sector, sure, but now that everything is more well defined, and every OS can read the FAT32 ESP? Never seen it...

At worst the UEFI boot entry is replaced. There are some really shitty UEFI implementations out there which only want to load \efi\microsoft\boot\bootx64.efi or \efi\boot\bootx64.efi, or keep resetting you back to those.

Assuming you were dumped into Windows suddenly, you can check if you have the necessary boot entries still with bcdedit and its firmware option

bcdedit /enum firmware

If you just have a broken order you can fix it with

bcdedit /set {fwbootmgr} displayorder {<GUID>} /addfirst

If you actually need a new entry for Linux it's a bit more annyoing, you need to copy one of the windows entries, and then modify it.

bcdedit /copy {<GUID1>} /d "Fedora"
bcdedit /set {<GUID2>} path \EFI\FEDORA\SHIM.EFI
bcdedit /set {fwbootmgr} displayorder {<GUID2>} /addfirst

Where GUID1 is a suitable entry from windows, and GUID2 is the one you get back from the copy command as the identifier of the new entry. Of course you will have to adjust the description and the path according to your distro and where it puts its shim, or the grub efi, depending on which you'd like to start.

Edit: Using DiskGenius might be a little more comfortable.