If you're jailbroken on iOS 8.3, you've likely been frustrated by the lack of Cydia Substrate support up until now. As you're no doubt aware of by now, Cydia Substrate hasn't worked on iOS 8.3 due to a fix that needs to be implemented by the folks at TaiG.
The good news is that the fix is out, and I've confirmed that it works. If you've jailbroken your device with the TaiG 2.0 tool yesterday or earlier today, you can use a simple .deb file install to fix Cydia Substrate in just a few minutes.
In this tutorial, I'll show you how to install the TaiG 8.3 Untether .deb on your jailbroken iOS 8.3 device and fix Cydia Substrate.