Boot apple logo, then one sec to black screen lit up means it's going into DFU mode due to corrupted firmware a.k.a unreadable system partition, if this is the result you either need to restore or NAND needs reprogrammed / reballed.
"Hi I’m Nirmal Singh. I’m currently having this issue with my mums phone. iTunes said it was because the iOS hadn’t been updated in awhile (which tbh, it hasn’t.) so that could also be ur issue.
UPDATE: I restored and updated the software. The phone now shows a regular screen. If you tried this and you cannot get the phone to restore, you may have a software issue - maybe the software encountered an interruption while updating, or when it failed. If you cant use iTunes, maybe try to update/restore using open source softwares.
If u wish to thank me, I’m a woman. Please do not red arrow me - I’m just sharing what worked for me. If it didn’t work for you, there are many possibilities as to why. Its not *my* fault and I’m not sharing anything offensive."
