I am trying to update a process used to remaster the Ubuntu 18.04 install image for 20.04 and running into a problem with extracting the initrd archive.
The command used is
cpio -id --no-absolute-filenames. When I use this same command to extract the initrd image from the 20.04 image, it extracts
kernel/x86/microcode/AuthenticAMD.bin and stops.
Inspecting initrd file contents I can see a "TRAILER" section showing that there are multiple archives in the file. As suggested in other threads about cpio archives, I tried to extract the compound archive as such:
cat initrd | while cpio -id --no-absolute-filenames; do :; done. In this case, the first entry extracts but then it has a bunch of "0 blocks" and doesn't extract anything else.
Does anyone know how this archive was created or how to extract it?