Hi folks. I wanted to try out latest Android beta on Funtouch OS 15 on my Iqoo 12 but there are too many features missing in it so I want to rollback to Funtouch OS 14. But using the instructions on Vivo developer's website, the local package is not detected from System updater application. When changing the ZIP file name to start with same letters as the Android 15 update package, it detects. 

Any way to downgrade to Funtouch OS 14 ?