Idk if the flair is correct, but not sure if this is a problem with Windows, Linux or my hardware. I have three internal drives in my pc. One 2tb M.2 formated in Btrfs for storing games and stuff, one 1tb btrfs hdd for booting Linux, and one 2tb M.2 drive for windows 10 whenever I need to use Ableton or Adobe programs. Yesterday I updated Windows because I haven’t used it since earlier this summer and now today all of a sudden I can’t seem to boot into linux anymore. I have tried booting from every disk manually through the UEFI, but no matter which one I choose the Windows logo pops up. Kind of annoying since I have a bunch of data that I can’t access through windows because of the filesystem. Anyone else experience this?
You can just use a live Linux installer to fix the GRUB if you have a flash drive at hand. Otherwise, try EasyBCD to add the Linux entries to the Windows boot sequence. Once you get into Linux, fix GRUB.