After installing Ubuntu, I used the tool boot-repair to get my laptop to load grub upon startup. Unfortunately, after a while, I have noticed that I can no longer boot from a flash drive (to reinstall windows or another linux distro) because the boot menu is filled up with Ubuntu entries. The UEFI firmware is behaving oddly and I'm scared that I will end up with a brick unable to boot any OS.
All options including "OS Boot Manager" take me to grub. The list does not scroll. From looking at the Windows 8 advanced reboot menus I know there are more options hidden down there. My settings indicate that secure boot is disabled. However, when I boot the flash drive from Windows 8's advanced reboot menu I get a message indicating that my computer will not boot from it (if you need the exact text I can try that again).
I imagine fixing this involves removing those extra entries from some EFI boot partition or something. Thanks in advance for your help.
My laptop is a HP Envy Spectre XT.