Chosen Solution
A few days ago my phone had around 70% battery, but when i got it out of my pocket I saw that it wouldn’t turn on. When I connected it through my computer, it started flashing the apple logo on and off. I tried to update it to ios9 (was at 8.4.1) but to no avail. I tried restoring it with a signed firmware from ipsw.xx, but when it finished deleting the old os and started “extracting software” it showed me error 21. Now when I connect either to the charger or the computer it shows me the connect to itunes screen. Can I do anything about this, or the phone is now a paper weight?
Put it into dfu mode and restore to a backup
