On Sat, 2017-06-24 at 11:08 +0200, Didier Kryn wrote:

>      Anyway I think there's a simple method to live without the 
> initramfs. Everything which is done from initramfs could be done the 
> same way from a disk partition, which might make it easier to debug: 
> have a /os directory containing all the necessary subdirs, /os/proc, 
> /os/sys, /os/dev, /os/run /os/usr, /os/lib, /os/var, /os/home... , mount 
> the first five, create the few necessary files and symlinks and 
> switch_root() to /os. This is exactly what your initramfs does.

Nope, that negates one of the principle reasons to use an initramfs in
the first place. You assume the stock kernel can see the drive where
you intend to put this new partition; one of the big drivers of initrd
in the first place was exotic hardware, etc. so GRUB uses BIOS
(including extension ROMs on controller cards) to load both the kernel
and the initrd so it can take whatever steps are needed, i.e load the
right modules, start lvm, setup encrypted filesystem magic, etc. to make
the main drive/partitions/etc. visible. Your idea could deal with most
everything that didn't need a kernel module but totally fails at that
task.