Afaik you're SOL.
As soon as Apple releases a new Firmware it stops signing the old ones.
As you did not updated to 4.2.1 you don't have you're SHSH Blobs saved.
That means if you still want to hold on to your JB, you should wait till the Dev-Team brings out the new 4.3 jb.
03-14-2011 11:56 AM