ogra@pi3:~$ cat /etc/systemd/system/pi3-init-bt.service
[Unit]
Description=Init LowLevel Bluetooth
[Service]
Type=forking
ExecStart=/home/ogra/bt-init.sh
[Install]
WantedBy=multi-user.target
ogra@pi3:~$ cat bt-init.sh
#! /bin/sh
set -e
MYHW="$(cat /proc/cpuinfo |grep ^Hardware|sed 's/^.*: //')"
HCIATTACH="/snap/bin/hciattach"
DEVICE=""
[ -x "$HCIATTACH" ] || exit 0
case "$MYHW" in
BCM2709)
DEVICE="Pi3"
OPTS="/dev/ttyAMA0 bcm43xx 921600 noflow -"
;;
*)
exit 0
;;
esac
echo "Initializing $DEVICE Bluetooth: "
$HCIATTACH $OPTS
echo "done ..."
ogra@pi3:~$