if you’re opening a shop or repairing phones is a serious side gig, then i agree with the recommendation of a temperature controlled heating plate. the precision, certainty and speed will definitely be more efficient.
since i’m doing rehabs purely as a hobby, i like to multi-purpose tools that i already have. i use a heat gun that i originally purchased for shrink tubing and paint stripping, although a regular hair dryer will work fine, you just need to learn how much heat to apply to get the adhesives to loosen up. [br]
if you really want something like the iOpener, there are plenty of DIY how-to’s on youtube that would seem to work pretty well.