Restore in itunes without updating
Finally, before attempting any of the methods we've highlighted below, we recommend disabling "Find My i Phone" first instead of doing so when prompted to streamline the process and stave off any potential hiccups it may cause.
To do so, open "Settings," tap your name, then select "i Cloud." (For i OS 10.2 and under, just select "i Cloud" from Settings.) Scroll down, tap "Find My i Phone," then disable the toggle for "Find My i Phone." You'll be prompted to enter your Apple ID password, so input your credentials to turn the feature off.
If you haven’t already done so, make sure to save your i Phone 4.1 SHSH blobs. You should now be on i OS 4.1 but the good thing is you haven’t updated your baseband.
At this point, you should be able to jailbreak using Lime Ra1n and even unlock using Ultra Sn0w.
This first method involves restoring your i Phone by way of a Cydia app.
The tweak, Rollectra, can be installed directly from Cydia without the need to install an external repo.
Everything is mainly done now including tweak injection except for a bug which breaks certain apps and causes stability issues.
Frankly, it’s often faster to just download the update files directly from Apple since they are delivered through a CDN they tend to go at or near your maximum download speeds.
It opens up a whole new realm for what your device can do, but it can also cause instability across the system and can dissuade you from getting future updates from Apple that have important features, bug fixes, and security enhancements.
For the most part, carriers can't block you from wanting to unlock your i Phone from their service, but jailbreaking is a whole different beast.
In any case, if you are running i OS 5 or later, you can use OTA to update i OS with no attachment to a computer or PC whatsoever.
If an update is available, tapping on Download and Install will finish the process for you with no attachment to a computer and no i Tunes at all. This is by far the easiest way to get the i OS update installed onto a device and requires no computer at all, the whole thing is completed on the i Phone or i Pad.