it could be interesting for Librem5?

I might bet PureOS need to stay within firmware-linux-free package borders, however perhaps someone have more time (as I don’t) to test (manage UEFI firmware updates) following options:

One (current Debian main repo):
~$ sudo apt install fwupd-amd64-signed
~$ sudo fwupdmgr --help
~$ sudo fwupdmgr get-devices

Two (Snapcraft):

~$ sudo apt install gnome-software-plugin-snap
~$ sudo snap install fwupd --classic

Three (future, as requires Debian Sid main repo):
~$ sudo apt install gnome-firmware (GTK front end for fwupd)

Four (Flathub):
~$ flatpak install org.freedesktop.fwupd

or (as OP initially linked to):

~$ flatpak install org.gnome.Firmware

If not pleased:
~$ flatpak remove org.gnome.Firmware
~$ flatpak remove org.gnome.Platform (3.34)
~$ flatpak remove org.freedesktop.fwupd

This is only a draft (not an answer) from my side, but will be pleased to get some news if this (which option, if any) can be useful, as OP asked/recommended (even if fwupd needs to be avoided). Also, if this should work (with time) just with UEFI someone might give an answer anyway.

P.S. @antpanlinux, maybe you should move this to PureOS category (topics).

I’ve asked the same in the past already. Here is a thread about it in general (for laptops or so):

Thanks for the instructions but fwupd has apparently not been compiled for arm64 yet using snap, using the other method results in an install but gnome-firmware reports the L5 is an unsupported device.

Have you gotten it to work properly, any tricks?

Not really, wasn’t focused in this direction at all. Anyway, here is where I found (as of today) this Debian EFI package:
bullseye/arm64/fwupd/download = fwupd_1.5.7-4_arm64.deb
bookworm/arm64/fwupd/download = fwupd_1.7.6-1_arm64.deb

You might test if dpkg -i fwupd_1.5.7-4_arm64.deb works for some particular purpose or just wait for PureOS developers to make some move in this direction (if and when needed).

There are a bunch of unmet dependencies that cant be resolved- fixed automatically.

  1. libfwupdplugin5, 2
  2. libflashrom1

And unmet dependencies there once i try to install those arm64 deb files manually.

Sure, I was aware you’ll see them. Only bookworm (not octarine repo from PureOS at this point of time) might solve this. I’ll test something tomorrow (and be back if success).

@Captain_Morgan, I’ve managed to install fwupd package on Librem 5, from amber main, but do not think or even know if it is needed or even related to … There wasn’t any usable response from: sudo fwupdmgr refresh.