Lateset version of Redsn0w i,e Redsnow 0.9.12b1 comes with an integrated feature for restoring SAM unlock activation tickets. Those who unlocked their iPhones using SAM unlock and backed up their activation tickets, can now restore them using Redsn0w.
Step 1: Download Redsn0w 0.9.12b1 and run it.
Step 2: Connect your device with computer.
Step 3: Navigate to Extras >> Even more >> Tickets and select your Lockdown.zip file.
Step 4: Redsn0w will pop up with a message that tickets uploaded successfully.
Step 5: Finally reboot your device.