Updated to 3.1 using itunes because I thought the jailbreak might be quicker..... Im with AT&T so dont need to unlock but really missin my jailbroke apps. I downloaded the Custom 3.1 ipsw and tried restoring to that but with no luck, Am I not able to do it now because I already updated thru itunes or what? Any advice or direction on this much appreciated!!

Thanks in advance.....

If you updated through iTunes, you need DFU mode to restore the custom IPSW:

- Connect your iphone to your computer with the USB cable.
- Hold power and home buttons during exactly 10 seconds.
- Release power button, but keep the home button pressed until iTunes detects an iphone in recovery mode.

Try this

I've tried that but keep getting error 1600..... Any other suggestions?

Try recovery mode instead of DFU: To put your iPhone into recovery mode, first disconnect your iPhone from USB cable and power off your iPhone. Then hold the “Home” button and connect USB cable again (it will power on the iphone). Keep holding the “Home” button until you see a dock cable pointing to the iTunes icon (or Steve Jobs logo for pwned iPhone). Now you are in recovery mode.