(adsbygoogle = window.adsbygoogle || []).push({}); Look, I'm sure a lot of people know this already. But I am going to post it.
Whenever itunes (Apple) updates, they have to have signed packages (Firmwares). Like 4.3.5, 4.2.1, 6.0, and so on. But I don't see why, but not questioning it. Back awhile ago, we were always able to downgrade to 4.2.1 without SHSH blobs, but since apple has been updating, we can't anymore. Right now, downgrading goes to 4.3.5 without SHSH blobs. I know tons about android and apple, but I never did save SHSH blobs, so i could restore to certain firmwares without errors that were not by passable cause of things running to bypass other errors. But every time you go on Cydia, look at the top at the firmwares to see what you can restore too. Those firmwares are without SHSH blobs. So we will wait to see the next firmwares apple signs for us. Thanks. c:
There Is a lot more about this, but i am sure you get the point now.

Only iPhone 4, iPod Touch 4th gen can be downgraded, and downgrading from 6.1.3 to 6.1.2 fails

i got a question about this i have 4.2 shsh blobs but not 5.0 blobs cant i just update to 5.0 from 4.2 it wont let me i get errors ffs but i can update from 4.2 to 6.1.2 ffs apple

it will only let you restore or update to apples latest firmware on iphone5 devices not sure about the 4 or 4 s