hi
i have failed to update my phone, my screen is black with iphone logo
Question marked as
Sounds like your iPhone won't come on and/or is frozen. If so go to If your iPhone, iPad or iPod touch won't turn on or has frozen – Apple Support
IF you are updating your phone, you will see the Apple logo on the screen, with a process bar while this happens.
You might also find this helpful if it is stuck or taking a while - Apple logo with progress bar after updating or restoring iPhone, iPad or iPod touch – Apple Support