Step 1~60 min total
Power the phone off completely
Hold power + volume down until the power-off slider appears. Slide to power off. Wait 30 seconds. Do not skip this — working inside a powered-on device with a lithium battery at any state of charge is an electrical hazard. If your battery is visibly swollen (screen bulging, back panel separating), place the phone in a fire-safe container before opening.
Was this step clear?