Now, Gabriel Aul has hinted that Windows 10 for Phones preview will have the roll-back ability and we think the latest Lumia software recovery tool update may be precisely for that.
@talkinglumia @andycoydwilson We’ll share more details later, but ability to rollback if you hit an issue is very important to us.
— Gabriel Aul (@GabeAul) February 5, 2015