If the phone has no power now, it needs to use the original charger to charge for 30 minutes and then turn it on. If the power is fully charged, please try to enter the engineering mode to clean the cache and then restart it. Clearing cache method: When the mobile phone is turned off, hold down the power key and the tone reduction key at the same time, enter the engineering mode, select the clearing cache option through the volume key, the system will automatically clear cache. After clearing the cache, select Restart to check whether the system can boot normally. If you cannot enter the engineering mode, it is recommended to take your mobile phone, warranty card and invoice to the local customer service center, and let the staff check your mobile phone and then provide help.