An alternative initramfs for Linux that offers additional technical capability. Boot from systems with some combination of encrypted storage, softraid, and LVM. Has a minimal rescue environment that you can SSH into. Even supports booting into and restoring suspended systems.
If you find yourself in a position in which you're running Arch Linux and your file systems are based on LVM, RAID, or both, and when you upgrade your kernel your system won't boot because the kernel isn't running the lvm2 hook, here's how to fix it.
mount -t procfs proc /mnt/procmount -t sysfs sys /mnt/sysmount -t tmpdevfs dev /mnt/devchroot /mntpacman -Syu and watch your kernel being built.exit and reboot. remove your stick and boot into your now working arch linux.