So I had my iPhone 4 running 6.0.2 jail-broken with evasi0n. Everything had been going good until last night. I was attempting to install Siri using Cydia, when my iPhone randomly turned off. I just assumed it was re-springing or something. The Apple logo appeared as it booted up, but it never fully booted up. It stayed on the Apple logo and did nothing else. I left it plugged in and left for school, then came back several hours later to find it still stuck on the Apple logo.
I tried doing a hard reboot, putting it into DFU mode, recovery mode, booting it holding the volume up button, everything, but nothing would work. I also tinkered around with TinyUmbrella but that didn't help either.
By now the Apple logo was gone, and now it's just stuck on a screen that has a picture of a USB pointing to the iTunes logo, prompting me to connect my iPhone to iTunes.
So I connected it to iTunes, and it told me that it recognized a device connected that's in recovery mode and that it had to be restored. By this point I didn't really care whether I lost my stuff on my iPhone or not, I just wanted my iPhone back.
So I tried to restore it, and I kept getting various error messages telling me I couldn't restore this iPhone (I got Error 21, Error 1601, and Error 1602).
Then, I tried uninstalling and reinstalling iTunes, and that didn't work either.
What else can I do? I'm so desperate and upset about this, please help!
Added (1). Eisa, I did try that.