TinyUmbrella is a tool developed by Notcom, written in Java language, that is used to save shsh blobs for the current firmware so you can easily downgrade your device whenever you update your iPhone, iPad or iPod Touch to higher version. To learn more about TinyUmbrella, you can visit TinyUmbrella FAQ.
Lets suppose you are on iOS 4.3.3 on your iPhone 3GS enjoying fully untethered jailbreak. You took the time to save SHSH blobs using tinyumbrella. Then you accidentally or for some reason updated to 4.3.5. Now you decide to go back to 4.3.3. Remember? you already had saved shsh blobs 4.3.3. Now using tinyumbrella you can easily downgrade from 4.3.5 to 4.3.4. What if you updated from 4.3.3 to 4.3.5 without saving shsh blobs? Sorry, you can’t downgrade.
Lets get to know how we use TinyUmbrella to save shsh blobs. The foremost thing to do is to download tinyumbrella form its official blog. As I mentioned above that this tool is written in Java language, you need to have Java installed on your machine in order to run TinyUmbrella.
Once you are finished with the downloads, run TinyUmbrella.
Now connect your device with computer via USB cable and let tinyumbrella detect it. Once it does, your device will be shown at the left-pane. Click on your device and then simply click Save SHSH button located at the right side. Shsh blobs for your current version are now saved. You can view them in General tab under All Saved SHSHs.
If you receive error while saving shsh blobs, go to Advanced tab and uncheck Request SHSH Form Cydia
option and then try again to save shsh blobs.
If you still get error, it means that Apple is not signing your current firmware version.
Now lets see how you can downgrade your device using tinyumbrella. Please note that you need to have shsh blobs saved for the firmware version and that IPSW firmware file you wish to downgrade to.
Launch TinyUmbrella, plug your device into computer and Click on Start TSS Server.
With Tinyumbrella running, launch iTunes. Select your device from the left pane and hold down the Shift key (Windows) or Alt key (Mac) and click Restore button. A new pop up window appear asking you to select the IPSW file. Select the firmware file you need to downgrade to and your device will get started to be restored.
Once the restore is complete, you will might get 1015 error. To fix this, go to Tiny-umbrella and click Exit Recovery button. That’s it. Your device has successfully downgraded.
If you are having problems or getting errors while dealing with the whole procedure, do let me know by commenting in the comments section below.