Jailbreaking has become so easy these days, within a matter of minute you can just jailbreak your iOS device, especially the Evasi0n Jailbreak tool makes it so easy to jailbreak your iPhone within a minute. Now come to the main point on how you can easily restore your iPhone without loosing your Jailbreak. Being an iOS user, you may need to opt this case, in case you want to sell your phone or may want to preserve your baseband. In that case you can not use factory reset your jailbroken iPhone option. So is there any way out? Yes, there is, thanks to the Developers who are always ready to develop such great, reliable and free tools for you.
Below is step-by-step tutorial how to wipe your iPhone without loosing your Jailbreak using the Semi-Restore Application, which is available for both Windows and Mac users.
How to restore iPhone, iPad and iPod without losing the jailbreak running on iOS 6
1. First of all you need to download the Semi-Restore application for your PC. [Download Link]
2. Note that Semi-Restore is only compatible with iOS 5.1-6.1.2, so make sure your device is eligible.
3. Now extract/unzip the download file and launch Semi-Restore application from the folder you have just extracted.
4. Now connect your iOS device to the PC and hit the Semi-Restore Button.
5. Now wait for the application to Wipe or Reset/Restore your device and once it is done your device will automatically reboot.
6. Once the process gets complete, it will prompt a successful message as shown in the below image.
Hopefully you have successfully Semi-Restore your iPhone, iPad or iPod Touch using the step by step tutorial to Semi-Restore your iOS device. If you do have queries or confusion, feel free to ask in the comment section.[source: iclarified]