BootSelector is a tiny GUI utility for setting any grub menu entry as default.
It also allows you to reboot into any OS/kernel in your grub menu.
The initial version has been tested on the latest Ubuntu 24.10 and should work on other Debian-based distributions as well.
An RPM for fedora will be released soon after more testing is done.
Yes, it only reboots into the selected entry ONCE without changing the default one.
does it use efibootmgr? if so,how is it handled on BIOS systems?
No. It just reads and parses the contents of /boot/grub/grub.cfg and updates /etc/default/grub