Comment 616 for bug 1734147

Hi. I'm experiencing problems that look very similar to the ones described in this bug report (can't boot from USB, changes made in UEFI won't save). This I noticed a couple days ago when trying to install a new distro, that failed with "Installing for x86_64-efi platform. Could not delete variable: interrupted system call. Grub-install:error:efibootmgr failed to register the boot entry: block device required"

I had Ubuntu 17.10 installed last year.

To make a long story short, I tried boot-repair and it failed, I tried installing other distros and got the same message. I tried upgrading the UEFI and it failed. It seems I can't even get a grub menu or prompt at startup. My computer boots to the message "no boot device on HDD". I can still boot however, if I pres F9 and manually choose "boot from EFI file" and select the proper .efi file (I can boot into Lubuntu 18.10).

My computer is an HP Pavilion 14-n249nf

I initially asked about the problem at https://askubuntu.com/questions/1104515.

1. how can I know for sure if this bug is the source of my problems ?
2. I followed the repair method described in the bug description. I can install kernel 4.15 without problems. But with no grub prompt at startup, how can I make sure to boot the right kernel that will fix my issues ?

thanks in advance for some answers