we must found at which step it stops.
do you know how to edit these scripts ?
and add just around "$i start"
# No sh extension, so fork subprocess.
echo "starting $i" >> /recalbox/share/boot.log
echo "starting $i done" >> /recalbox/share/boot.log
then, save your overlay (see the wiki), reboot, wait during the freeze.
open your key, and check the boot.log file.