HiYou could start by going into recovery and wipe cache and dalvik. If that doesn't work then try flashing firmware again. If you have done a back up first I would use CSC not Home CSC
I have the Aust delivered S8.
After jailbroke it, when i restarted the phone, i got the dreadful only official binaries are allow .....etc. I have tried a heap of difference firmware here but none have been able to bring my phone back to life, please help