I am reminded of the ability MANY years ago to write the kernel file directly to a floppy disk, or start of a hard drive and somehow being able to boot that way.
I just can’t recall how I did it, or WHY I did it.
Back when the kernel would fit on a floppy disk. I am truly showing my age.
6 yr old grandson found a box of old floppy disks and was asking what they were. He started stacking them up making card houses and roads for his matchbox cars. Glad he got some use out of those recycled AOL floppies.
you can backup your EFI partitions, in case you mess them up. I find it a good idea to back them up in any case, I have had EFI partitions get Filesystem corruption.
also the tool rEFInd can work as an alternative boot menu it has the ability to scan the entire system and show all found Bootable OS at boot time.
So with rEFInd, you install it, set it as the default, and it should show windows automatically.
it looks nicer than systemd-boot and grub as well. And it can even show bootable USB flash drives, and has a few other features.
And does uninstalling a flatpak app also uninstall flatpak dependencies that came with it?
from what I have seen, NO it does not do so automatically. there is a flatpak command option to clean out unused runtimes, and another to remove user data.
delete app data after uninstalling?
you either manually delete the data, or there’s some flatpak command option, or you can use a tool such as warehouse which is available as a flatpak.