Some users asked: about the solution now you can fix it.
Step 1: Open Redsn0w 0.9.6rc14.
Step 2: Select the same firmware you used when jailbreaking.
Step 3: Once IPSW identified, click "Next"
Step 4: Uncheck "Install Cydia" and select "Just boot tethered right now" and click next (Don't worry this will not affect your untethered jailbreak)
Step 5: Here, I recommend that you go ahead and be proactive by putting your iPhone into DFU mode prior to clicking "next".
Step 6: Once you click "next", the iPhone will go through the tethered boot process once. When you return to your home screen, Cydia should be back to normal.
I tried it myself and it worked well, tell me what about you.