The battery in my 2-year-old iPhone 6s would no longer hold a charge.
The repair went OK. These phones are always WAY more difficult to open than the videos and guides would have you believe. I still am skeptical a suction cup alone can break the glue. I applied pretty strong, constant pressure for 10-15 minutes and it ever, ever so slowly got the tiniest crack going. But no spludger was going to fit in the something that size. I remain convinced the best and only tool for "first contact" is a single edge razor blade over the headphone jack, which will both fit and cut the glue. That let's you get it open enough that you can switch to plastic spludgers. (I even tried some heat from a heat gun to soften the display glue, with little effect, but I was also kind of tentative with this as I didn't want to cook the display.)
I was able to get one of the adhesive strips out OK and like the technique I read here that involves twisting the adhesive around the tweezers as you pull straight down. This let's you keep an even and high torque from the tool close to where it emerges from under that battery.
The other strip was less successful, I got about half out before it snapped and then had to do the "pry of shame" without any heat using a spludger and plastic card (and trying not to to compromise the integrity of the old battery). I could also use the "rolling tweezers" underneath the battery to pull more adhesive after I got it up off the deck a bit.
Had no trouble at all with the new adhesive strips' backing not peeling away, so maybe that problem has been addressed.
I seem to have glued the new battery down a hair closer to the battery connector than the old one, as connecting the new cable required bending it "up" a bit to shorten it., which did not seem right but worked OK.
Closed everything up and didn't use any new display adhesive because I keep the phone in an otterbox and am not worried about moisture resistance. And if I ever need to get in there again, I don't want to fight that miserable glue. The display fits plenty tight, thank you very much.
New battery works great and looking forward to getting another 2 years out of this phone and not paying Verizon any more $$$ for the device!
1. Use a single-sided razor blade for "first contact" as soon as you get the glass up enough.
2. Don't bother disconnecting the display. Strap it to something solid at a 90 degree angle with a rubber band. You'll have plenty of room to work. Just don't jerk the base around.
3. "Rolling tweezers" to remove adhesive work well.
4. Pay attention to where the battery connector is coming down as you set the new battery so the connection is the right length and you don't have to fiddle.
5. iFixit stuff is expensive. The battery and tape cost $40 shipped. I hear you can get a guy at the mall to do this job for $25 here in CA. And obviously, the same parts are available on eBay and Amazon for less -- BUT, I keep ordering from iFixit because every part appears to be checked for quality and authenticity before they go out so I don't have to worry that I'm putting inferior crap in my phone -- especially when it is such a PITA to get in there and do this work.