Never have I seen such ridiculous design. Despite what this blog claims there is no way the blue plastic tool or guitar picks will remove the back cover. The only way I was able to even slightly part the side seam was with a sharp flat bladed screw driver driven in by a clamp - which bent up the aluminum frame. Now using to the blue plastic "tool" (junk) I pretty much destroyed it working it around. The sharp metal back cover just cuts right into it shreds it. Back to metal flat bladed screwdrivers.
Got back over off - but frame no longer straight. Carefully straightened, Replace the battery & re-assembled. Unit beeped - Screen came on and shows cracks and stress marks but no menu.
Because of awful design I destroyed the screen just trying to get the back cover off to simply replace battery.
So - since Apple was so determined not to let me perform a simple battery replacement I am now equally determined NEVER to buy any Apple product again. So much for being a good design company - Total crap.