Comment 26 for bug 1925010

For your information, I have an HP EliteBook 840 G2, I did a fresh install of 21.04 and had the same issue, it uses an "EFI v2.31 by HPQ".

I used following work around which worked.

What made the trick was the following changes in the BIOS Setup (after computer start push F10 - go to System Configuration - open Boot Options):
Check Customized Boot
Check off SecureBoot
Boot Mode: choose UEFI Hybrid or UEFI Native (I chose UEFI Native)
UEFI Boot Order: put Customized Boot to the top
Define Customized Boot Option: choose Add + put the setting: \EFI\ubuntu\grubx64.efi

Source: https://askubuntu.com/questions/244261/how-do-i-get-my-hp-laptop-to-boot-into-grub-from-my-new-efi-file