Full wipe/factory reset. Just flash the rom zip file no Gapps already there and then get the Kernel Boeffla 7.7 and the Apk on play store. If you have any problems after installation like unfortunately stop running. Backup your files and do a Format on your cell just in case any bugs left on, do a clean installment and start from scratch. then flash the ROM zip file.
Is it required to flash Kernel Boeffla 7.7 after the flashing the ROM?