I am trying to create modify an u-boot filesystem image. At first I tried to extract, modify and then pack it again, but that didn't work, because extracting and repacking seems to mess up the ownerships of the files. So I tried to modify it, without explicit extraction using file-roller. This should work, but sadly file-roller saves the file in the wrong format and doesn't let me change the format.
So is there a way to convert a .cpio to newc-format without extracting it?
Before I used the following commands to extract and pack:
cpio -idv --no-absolute-filenames < ../filesystem.cpio find . -print | cpio -ov -H newc > ../output.cpio