raspi init_debug

init_debug.sh

#!/bin/sh
# This script is a template for debugging things that run as init (PID=1)

test_me () {
	echo hello world!
	lsusb
}

printf '\033[2J\033[0;0H' # clear screen
mount -t proc proc /proc
mount -t sysfs sys /sys
mount -t tmpfs tmp /run
mkdir -p run/systemd
mount /boot
test_me > /boot/log
cat /boot/log
mount /dev/mmcblk0p2 / -o remount,rw

# this gives you an interactive shell on uart0, here you can edit
# the contents of this script and read the output of test_me in /boot/log.
# ctrl-D to reboot when ready to try again
sh

# clean up
rm -r boot/log
sync

# reboot
echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger