How to add/change efi entries on Dell Wyse dx0d thin client (weird behavior)?

Question

Dell

There is a thin client Dell Wyse d-series 500 dx0d. Secure boot disabled
Tell me how to defeat efi.
When installing efi of any linux distribution, there is always a grub installation error at the end. And of course, it just doesn't load then. Grub is installed in the EFI partition but is not registered in the bios. I run it through the refind located on the flash drive.
Having started linux, I try to edit the efi entries myself through efibootmgr. The commands efibootmgr -c -L "xxx" -l "xxx" -u 'xxx' pass without swearing, but they do not lead to anything either.
I can't start efishell, stupidly goes into reboot. I
thought that you can't change anything (add/delete) lines, but after the next installation of ubuntu, a new entry appeared in the boot menu "ubuntu", HOW?
This effect has not been replicated.
Can anyone come across a similar, tell me how to overcome it? How to make it so that when installing grub, he would register all the lines in efi and not swear at it? Why doesn't efibootmgr result in anything? Why won't efishell start? I've been struggling with this for a week, please help)

Answer 1

In general, I decided myself,
why didn’t efibootmgr work? I didn’t understand
) grub was not installed due to efibootmgr not working properly
) EFI Shell started, but the earlier version is more detailed
There, entries were added and deleted, everything was as it should (via bcfg)
But it stopped entering the BIOS and boot menu from the button;)
Flash bios from a flash drive did not work on this miracle, but fortunately it turned out to be a programmer ( firmware for Wyse 5010 Thin Clients
After all the problems disappeared, grub was installed by itself, efibootmgr does everything they want from it.