Hello.
I made an app which is exactly like Luca's Yalu app but it will start the jailbreak without Cydia Substrate.
You should use this if your phone doesn't start after jailbreaking it. I had a problem where a tweak made it so I couldn't start my phone, not even in safemode and that's why I made this.
I recommend that you install this even if your phone isn't f**ked right now because it may get because the jailbreak is in beta.
The difference between this app and Luca's is obviously that it'll not start with Substrate but also some text changes, color changes and also a popup which tells you how to start Substrate after you have started the jailbreak.
http://imgur.com/a/OSCGV
How to start Substrate after jailbreaking:
-Go to MobileTerminal, if you don't have it then install it from Cydia.
-Type "su".
-Type in your root password, it's by default "alpine".
-Type "etc/rc.d/substrate".
-Type "killall -9 SpringBoard".
These instructions are also in the app.
http://www.mediafire.com/file/iysq4pbhfaj9ebm/YaluCustom.ipa
It's a remake of Yalu102 Beta 7.
Install with Cydia Impactor.