Comment 2 for bug 1900335

Relevant lines from DpkgTerminalLog.txt:

Setting up linux-firmware (1.187.3) ...
update-initramfs: Generating /boot/initrd.img-5.4.0-51-generic
[..]
cp: cannot stat '/etc/ykluks.cfg': No such file or directory
E: /usr/share/initramfs-tools/hooks/yubikey-luks failed with return 1.
update-initramfs: failed for /boot/initrd.img-5.4.0-51-generic with 1.
dpkg: error processing package linux-firmware (--configure):
 installed linux-firmware package post-installation script subprocess returned error exit status 1

You have yubikey-luks installed, which hooks into update-initramfs and attempts to load a configuration file /etc/ykluks.cfg - which does not exist. As a result, the hook, update-initramfs, and configuring the linux-firmware package (which triggers an update-initramfs) fail.

This is probably a configuration issue. It could also *possibly* be a bug in yubikey-luks (*may* want to just warn if this configuration file is missing), so I'm reassigning to that for now.

Note that yubikey-luks is in universe, so community maintained.