bester

Instructions for replacing the seal are here: Remplacement des bandes adhésives fixant l'écran d'un iPhone

I just had the same experience. The blue backing would not separate from the adhesive.

I tried a new tactic: Remove the ping backing and apply to the case, and then remove the blue backing. No go. It stuck to the blue backing more than it did to the case.

I should have just left the remains of the old strips in place. Instead, I just installed the battery without the adhesive. I hope that’s good enough.