cp /usr/lib/systemd/system/kodi-autostart.service /storage/.config/system.d
and edit file /storage/.config/system.d/kodi-autostart.service
But I doubt this would work because autostart will be just skipped.
Put this in autostart.sh and it will delay starting kodi until path exist. Or 15 sec max.
cnt=1
while [ $cnt -lt 15 ]; do
if [ -d /var/media/USBHDD/recordings ]; then
sleep 2
break
fi
let cnt=cnt+1
sleep 1
done
Also create folder /storage/.kodi/addons/driver.dvb.delay_mount/bin and create file /storage/.kodi/addons/driver.dvb.delay_mount/bin/userspace-driver.sh with content
cnt=1
while [ $cnt -lt 15 ]; do
if [ -d /var/media/USBHDD/recordings ]; then
break
fi
let cnt=cnt+1
sleep 1
done
This will delay starting tvheadend addon until path exist.
One other option would be to restart PVR client from userspace-driver.sh.