Update an initramfs with contents of a directory without root
This tool allows you to take a initramfs and add contents of a directory to it. This is very useful if you need to test initramfs, you can simply take the original and add your files "over".
Also, because it does not extract the original cpio archive, it works without root.
Usage: overlay-initramfs [ options ] source-initramfs directory [output] create an initramfs that has 'directory' overlayed on top of the source-initramfs. This relies on the fact that you can append cpio archives to an initramfs and the kernel extraction just puts one on top of the other.
- This probably needs to be updated with the new style initramfs that have an 'early' and 'early2' directory in them. In newer ubuntu (18.04+) there is a tool 'unmkinitramfs' that unpacks initramfs, but unfortunately there is no "re-initramfs" that would re-pack the unmkinitramfs output.