Every iPhone, iPad and iPod user wants an ability to downgrade the firmware either if the firmware is resulting in loss of software unlock due to baseband upgrade or if the firmware is buggy. But Apple does not like this idea of downgrading the firmware therefore its restricted.
Jailbreak community has come up with an ides of saving the authenticity/verification signatures named as Blobs. Blobs are basically 1024 bits RSA signatures used for verification of validity of firmware being installed. So the simple theme is, if you have you SHSH blobs saved you can revert back to older firmware. For example if you have saved SHSH blobs for 4.2.1 and you accidentally upgraded to 4.3.4 so you can downgrade to 4.2.1 using TinyUmbrella.
- Download TinyUmbrella 5.00.06 onto your computer from here
- Run TinyUmbrella and you will see this kind of interface
- Now connect you iPhone, iPad or iPod with computer and you will see your Device name under connected devices on TinyUmbrella. After you see your device name click it to see its information on TinyUmbrella.
- On the right hand side you will see a Save SHSH button, click it to start saving you SHSH blobs. On completion you will see your Phone’s blob under Saved SHSH blobs as shown in snap below.
- You have successfully saved your SHSH blobs from the firmware you are currently running. If your blobs have not been saved then you can click advanced tab and try un-checking “Request SHSH from Cydia” and Press Save SHSH again. Hopefully this time it will work.
- You can downgrade you firmware if you have already saved your SHSH blobs on previous version e.g. you have saved blobs for 4.2.1 and currently you have upgraded to 4.3.4 and want to go back you can do so by following this procedure. Simply run TinyUmbrella and connect your iDevice with PC or Mac. Start TSS server by clicking “Start TSS Server” below.
- Keep TinyUmbrella Running and open iTunes. Press shift+restore and select the firmware you want to downgrade to. You can download firmware from here
- Once the restore will complete it will give you an Error 1015. On getting this error close iTunes and open TinyUmbrella and right click your device under Recovery Devices and press Exit Recovery and you are done. Congratulations your device is downgraded.
- If your device is not recovered, goto Advanced tab and un-check “Set hosts to Cydia on exit” and perform restore again. Hopefully it will work and if not feel free to comment you problem below.