There are cases when your iPhone is stuck in recovery mode and you need to save its SHSH via TinyUmbrella locally to allow you downgrade to an earlier iOS version. Fortunately, there is a relatively easy way to do this.
Each iPhone comes with an ECID (Exclusive Chip ID) which is a 16-digit hexadecimal number. Once you have the ECID, you can create a custom iDevice in TinyUmbrella to save your SHSH blobs locally from Cydia.
2. Launch the program and check Show Config Descriptors option under Options.
3. Go to File > Refresh.
4. Find Apple Recovery (iBoot) USB Driver option in the left-panel. On the right panel, you can see the ECID in the descriptor fields. It should be something like ECID: 000xxx…
5. Now download the latest version of TinyUmbrella [current version as of today is 4.33]
6. Launch TinyUmbrella > go to Advanced tab and check Request SHSH from Cydia.
7. Go to General tab and click on Manual ECID button. Enter Display Name (any name you wish), ECID and select your iDevice model. Click Create Custom Device.
8. Choose the device that you just created under Custom Devices on the left panel and click Save SHSH.
9. Click Start TSS Server and restore using original or custom firmware with iTunes once your SHSH is saved locally.
Mac tutorial to come soon.