thanks a lot for testing @Manoj ! but please do not ignore the other thread. it actually did not work for other people and was fixed by using fastbootD mode. also we needed to run the script twice. once in the fastbootD where it only fails in the very end and once more in the fastboot mode accessed via the freshly flashed e recovery.
this could actuallyb be the difference — did your people test this on a new phone as delivered by Fairphone or did they already start with an e recovery on the phone?