HOW To Fix White Cydia Icon After Jailbreak iOS 5

Step 1: Open up RedSn0w.
Step 2: Select browse and load the same firmware you used when jailbreaking.
Step 3: Once the IPSW is successfully identified, click next.
Step 4: Uncheck “Install Cydia” and select “Just boot tethered right now” and click next.
Step 5: Put 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.
NOTE : if you use Redsn0w 0.9.9b4 or b5 there is no need to select firmware , just select ” Extras “  then ” Just boot” , its done.