This repository contains proof of concept code for performing first-boot initialisation on a Raspbian system without requiring access to the ext4 partition.
A working Raspbian system is required for bootstrap purposes.
This software (such that it is) is under the ISC licence; see the file
raspi-hacks.sh for details. Note, however, that busybox (which is a
dependency of this script) is licenced under the GNU General Public
License version 2.
A sideways look at Bytemark's pi-init2 was taken to see how other people solve this problem.
Mount the vfat partition of the Raspberry Pi that you wish to perform the first-boot setup on.
On the running Raspbian system from which you are bootstrapping,
install busybox-static and copy /bin/busybox to the root of the
vfat partition that was just mounted.
Copy the script raspi-hacks.sh from this repository to the root of
the vfat partition.
Make a copy of cmdline.txt in the vfat partition called
cmdline.txt.new. Modify the parameters in the original cmdline.txt
file which look like this:
root=/dev/mmcblk0p2 rootfstype=ext4
to something like this:
root=/dev/mmcblk0p1 rootfstype=vfat rootflags=umask=000 init=/raspi-hacks.sh
(This makes the assumption that the parition layout of your SD card is the default Raspbian layout, i.e. that the vfat boot partition is the first on disk, and the ext4 root partition is the second.)
Put the SD card into a Raspberry Pi and boot it up. With a bit of good
luck, it should boot, write the string "Hello, World!" to a file
called /hello on the root filesystem, and then reboot into the
normal Raspbian system.
The statically linked version of busybox is
used (in the intended "swiss-army knife" manner) to provided the
commands needed to run raspi-hacks.sh in an environment where
standard Unix utilities aren't available. This shell script mounts the
root filesystem, performs initialisation tasks, modifies boot
configuration and then reboots.