I can see my
initrd is occupied almost 90 MB of disk but after extracting it via
cpio , it contains only a 30 KB microcode :
$ cpio -it < initrd.img-5.4.0-18-generic . kernel kernel/x86 kernel/x86/microcode kernel/x86/microcode/AuthenticAMD.bin 62 blocks
I know that there should be a lot of files and tools which are needed by the kernel in the first stage of booting , but I cannot find anything useful in it.
$ file initrd.img-5.4.0-18-generic initrd.img-5.4.0-18-generic: ASCII cpio archive (SVR4 with no CRC)