EFI can also live in firmware memory.
You can pull the linux drive, boot from the windows drive, and if one of the firmware updates was for efi, windows will trash the entry for your Linux disk.
This has happened for me many times, I had to use a grub rescue disk to rebuild the efi table.
The boot entries live in firmware yes, efibootmgr can create and remove them. The are pointers to the bootloader. Many systems can boot from the disk itself without the entry, the entry just makes it pretty (“Fedora” instead of NVME1).
I’m not exactly sure what you’re suggesting. Isn’t that more or less what I just said?
Somewhat. One, a system can be bootable without the entries because they are just pointers to the actual bootloader, so even if windows does the stupid and deletes them it isn’t the end of the world. It does depend on your specific firmware though.
Also two, you can write them again with a single line in efibootmgr, they’re just saying “if I click Fedora load the shim from the EFI system partition on disk 1”.
This is very different than the old world where windows would delete your bootloader entirely and the MBR couldn’t be easily explored. They live in the efi system partition instead - or at least the shim does- and typically every OS leaves the other ones alone (even Windows, except in this case, although it didn’t touch the shim itself).
The initial comment was about the bootloader and really only applies to MBR partitions.
