Why are there 3 same Ubuntu options in rEFIt menu?

[jason121]

I install rEFIt to make dualboot menus on Mac. And, after I installed Ubuntu 14.04 LTS, why are there 3 same Ubuntu options in boot menu? Just like that below...


Boot EFI\ubuntu\MokManager.efi from EFI
Boot EFI\ubuntu\grubx64.efi from EFI
Boot EFI\ubuntu\shimx64.efi from EFI
Mac
...

What are the 3 options different?
May I customise to only one option for Ubuntu?
When I select any one of Ubuntu options, I still need to select which action I want

Ubuntu
Check disk
...


Why I can't login Ubuntu since I've already selected to launch Ubuntu in boot menu?

[oldfred]

They are not the same.
MokManager is the secure boot key editor.
grubx64.efi is standard boot
shimx64.efi is for secure boot.

All but grubx64 may not apply to a Mac as that is more for the newer PC systems with the newest UEFI that implements secure boot. Mac has an older UEFI that does not use secure boot.

I would think you could remove shim & mokmanager files from efi partition, but do not know how to update rEFInd or if it will update itself when files are deleted.