iPhone 7 no longer boots up after battery calibration
i recently changed the battery in an iPhone 7. The replacement went smoothly (or so i though). The phone booted up and I started the battery calibration process (charge until 100% and then wait two more hours, then drain the battery then charge it back up). Once the battery was drained, I plugged it back to charge it and left it for a couple hours (after it showed the apple logo). Once I came back a little while later, the phone was completely dead (no vibrations, no force restart, nothing). I tried putting back the original battery but I still don’t get anything. Any Ideas ?