I'm really hoping one doesn't require blobs. I REALLY need to swap out my iPhone 4. My power button is recessed and gives next to no feedback but I don't want to swap it and risk getting an iPhone with 4.2.1 pre-installed. Sigh... it's a 50/50 chance I'm not willing to take.
I've taken it apart and fixed it and it just does it again after a day or so.