This page documents things useful for being able to fix things in the initramfs stage of booting.
/usr/share/initramfs-tools/init - main init script
/usr/share/initramfs-tools/scripts/local-* - scirpts that run for the local boot method (the default). Other boot methods could be nfs (order: top, premount, bottom)
LVM roots: root=/dev/mapper/vgname-lvname
break=NAME, break at these given places (see initramfs-tools/init for locations, such as top, premount, bottom, mount, mountroot, init)
debug, or debug=* - be more verbose (set -x), and log to /dev/.initramfs/initramfs.debug
There are two sources for hook directories, /etc/initramfs-tools/scripts/, and /usr/share/initramfs-tools/scripts/.
The hooks.d directory is called to move important files into the initramfs when it is created
The conf.d is moved into the initramfs as configuration variables.
The general boot sequence is:
- parse boot arguments
/scripts/$BOOT, BOOT=local or nfs
mountroot function - defined in scripts/BOOT
(for local) calls pre_mountroot (and scripts/local-top/*)
(for local) calls scripts/local-premount/*
(for local) mounts
(for local) calls scripts/local-bottom/*