yo i made this tut
First i wanna give some cred to Applejuiced, he supplied key information.
Stitched firmwares are useful for restoring an iDevice and staying on the same firmware without the need of backed up shsh blobs
You will need:
redsn0w 9.9b8
http://blog.iphone-dev.org/redsn0w-iOS5#idc-cover
your current firmware that you are on (get it yourself)
for the examples used i was on a iPhone 4 4.3.5, so your files will look different.
1.) Open redsn0w 9.9b8, go into Extras > SHSH Blobs > Fetch, hook your device up and follow the on screen instructions. You will get a .plist file (shsh blob) for the current version you are on.
Should be like this
748769141644-iPhone3,1_4.3.5_8L1
2.) Go into Extras > SHSH Blobs > Stitch custom .ipsw. For the shsh file needed, point to the .plist file which was created from step 1. For the .ipsw, select the one which you should have downloaded.
After it has been generated, the file should be something like this
748769141644_iPhone3,1_4.3.5_8L1_Restore.ipsw
3.) Go back into redsn0w and go into Extras > Enter PWNED DFU mode. Follow the onscreen instructions.
4.) Open iTunes, connect your iPod and press restore holding shift (option on mac) and select the .ipsw that was generated by redsn0w
748769141644_iPhone3,1_4.3.5_8L1_Restore.ipsw
iTunes will restore your iPod to the firmware it was previously on, but towards the end you will recieve Error (1) and it will be stuck in recovery mode
5.) Open redsn0w (for the last time ) and go into Extras> Fix Recovery. Follow the onscreen instructions.
If all these steps are done correctly you will be back on the firmware that you started with, w/o any previous shsh blobs.
Good Luck