debugging initramfs boot process, install client can't mount root file system

[Thomas Lange]

If you have any troubles during the boot process of your install
clients and they can't mount the nfsroot, you like to have a shell for
debuging.

You can get a shell by adding break=bottom as kernel parameter (in
a pxelinux.cfg file). This stops the boot process and spaws a shell
within the initramfs. Other values for break= can be found if you search
all initramfs scripts for the subroutine maybe_break:

maybe_break top
maybe_break modules
maybe_break premount
maybe_break mount
maybe_break mountroot
maybe_break bottom
maybe_break init
maybe_break live-premount
maybe_break live-bottom
maybe_break pre-mdadm
maybe_break post-mdadm

-- 
regards Thomas