uefi - How to delete OS from boot menu

After installing fedora and Centos and other OS now I have them all showing in my Boot menu [F2] on start up not the menu form the OS even after deleting them and reinstaling other OS - Ubuntu -so It just shows one when the OS starts but when I go to UEFI setting I still find all the old ones they instruct you to use DEL to take them out but that does not work

Answer

The menu to which you refer is the firmware's built-in boot manager. Its entries are stored in NVRAM, and can be edited by any number of tools in various environments:

• Some EFIs provide a means to do this via their setup utility. Details vary from one system to another, though, and many don't permit you to add or delete boot manager entries.


• The EFI version 2 shell provides a command called bcfg that can do the job. You'd need to do bcfg boot dump -b to see the entries, then bcfg boot rm # to delete entry number # -- # must be the number associated with whatever entry you want to remove.


• In Linux, efibootmgr can do the job: Type efibootmgr or efibootmgr -v to see the entries, then do efibootmgr -b # -B to delete entry #. (You must type these commands as root or using sudo.)


• In Windows, the EasyUEFI tool should be able to handle the job, although I've only toyed with it briefly, so I can't give detailed instructions.

Be aware that in any of these cases, you may have leftover files on your EFI System Partition (ESP). You can delete them through normal file-manipulation commands, although depending on your OS, you may need to explicitly mount the ESP. If they aren't referenced, the files won't do any real harm, unless they consume so much space that they prevent you from installing another OS or updating your boot manager. The files will normally be stored in subdirectories of the EFI directory on the ESP; most OSes create subdirectories named after themselves or the companies that create them, such as EFI/ubuntu for Ubuntu or EFI/Microsoft for Windows.