Okay, so here's my problem. So, yesterday I bought a used iPhone 3g, for half an hour or so I was stuck on the pineapple screen, possibly just because that was my first experience with an iPhone. Now, when I finally got it in DFU mode, I connected it to a computer to upgrade from iTunes, this went well, until the update was interrupted since the laptop ran out of power. After this, the phone would boot to an apple logo. Now, third time, I tried upgrading again, this time, my dad pulled the chord out in the middle, and now whenever I try to upgrade (Even in DFU mode) I just get a 1015 (Trying to downgrade) error. Also, whenever I start the iPhone (Except when I put it into DFU, ofcourse) I get stuck on the recovery screen, I looked up how to get out of it, but it doesn't work. Appearently I'm in a "Recovery screen loop". Now, what should I do? Is my phone unusuable now? Also, the previous owner resetted it, so it's not jailbroken.