Comment 5 for bug 1840945

@xnox, thank you, in #3 I was testing date.img as a plain cpio without compression,
while with your updated lz4/xz commands, it appears that when date.img matches the compression of initrd.img, then it works fine.

So the problem only happens when mixed compressions are used.

Btw, the reason I was trying that, is that in the new version of the "ltsp" netbooting package, we send all the netbooting code as an additional initrd.

So if we can't use mixed compressions, we'll need to provide a different initrd for each image/chroot/vm/live-cd that the ltsp sysadmin will want to netboot.

If the plans to default to lz4 initramfs are cancelled, then ltsp will work anywhere with a single initrd, from jessie and 16.04 to buster and hopefully 20.04. :)

Otherwise... where should we hunt the bug? In the kernel decompression code, or in mkinitramfs?