You can use Cydia Impactor if you need to un-jailbreak an 8.1-8.4 device without restoring. To search this page for a keyword (such as "baseband" or "SHSH"), use Ctrl-F on Windows, Command-F on Mac, or this feature in Safari on i OS.
Then use your Pay Pal account to purchase products in Cydia.
Normally the error should not appear, but if you see the error blinking on your screen then we found the answer on what went wrong!
In our case, the error appeared while jailbreaking i OS 5.1.1 using Absinthe 2.0.1, but this error can also appear in other processes.
If you missed the news, you can check out everything about the release of Absinthe 2.0.1 to jailbreak any i Device.
While we where trying to get our i OS 5.1.1 SHSH Blobs using Tiny Umbrella, i Tunes showed a message that for some reason we cannot restore i OS 5.1.1 using Tiny Umbrella.