[derefr]

> how do you unmount without being able to read the binary

We have enough RAM now that there's no reason (even on embedded devices!) to ever unload the initrd/initramfs. An OS should be able to be configured such that you can unmount your rootfs whenever you like, and just automatically be de-pivot-root'ed and end up back in your initramfs, where you can mount the rootfs again.

[joushou]

What's your definition of embedded? It's not embedded if you're running a full blown OS on a regular ARM chip.

Anyway, you could make a ramdisk, put things in it and put it in your path. I doubt that a linux box will survive a dead root without hardcore sysadm skills, but it should work on plan9. Initrd is not meant to stay behind after boot, though.