[Unit]
Description=Unbind ttyAMA0 from pl011 and reload bbserial
DefaultDependencies=no
After=systemd-modules-load.service local-fs.target
Before=bbctrl.service
ConditionPathExists=/sys/bus/amba/drivers/uart-pl011

[Service]
Type=oneshot
RemainAfterExit=yes
# Tolerate the device already being bound elsewhere or the module
# already being loaded — the goal is the end state (bbserial owns
# ttyAMA0), not running the steps.
ExecStart=/bin/sh -c '\
    echo 3f201000.serial > /sys/bus/amba/drivers/uart-pl011/unbind 2>/dev/null || true; \
    /sbin/modprobe -r bbserial 2>/dev/null || true; \
    /sbin/modprobe bbserial \
'

[Install]
WantedBy=multi-user.target