As the original yalu jailbreak didn’t have support for mobilesubstrate but now in beta 4 it is supported and mobilesubstrate is necessary for tweaks to work properly. There are also some other issues that are fixed. The hacker, Luca Todesco advised the developers to hard reset their devices and then jailbreak again.
The hacker is working on the stable and public release for the iOS 10 jailbreak but this beta isn’t stable and it is advised that only developers should jailbreak their devices using yalu jailbreak and other users should avoid it because there is a possibility that they might have to upgrade to iOS 10.2 and lose their chance for jailbreak.
I am eagerly waiting for iOS 10 jailbreak. Are you? Let me know in comments below.