BigBoss posted on his blog yesterday that if you enjoy using jailbroken tweaks such as winterboard and sbsettings, hold off on the big March 11th update. It’s always a cardinal rule to wait for the new jailbreak before updating to Apple’s new firmware, this time he says, use extra precaution.

Apple will be using ASLR (Address Space Layout Randomization) in its new iOS , which BigBoss says will damage the way mobile substrate works. It looks like the 4.3 jailbreak is going to need a patched mobile substrate file. Mobile substrate is just a few dynamic libraries of code in your iPhone’s OS (like windows .dll files)…

It has multiple purposes, but what it’s generally used for is a fail safe. It’s what tells your “SpringBoard.app” to run in the event an application crashes. Otherwise you’d have to force reboot your iPhone. Applications crashing, with no code to call it back to the home screen, is why you see so many of your Android friends pulling their batteries out 🙂

So we thank BigBoss for the heads up, and urge you as well to avoid downloading Apple’s new 4.3 update this Friday. With previous beta versions of iOS 4.3 jailbroken, I don’t think it’ll be long after the big day before we see an official jailbreak with the mobile substrate fix.

As always, we will let you know as soon as that’s available. Has anyone updated to 4.3 GM and noticed issues with any of their jailbreak apps? Are you on 4.2.1 right now and plan on downloading the new update regardless? Tell us below!