Yuzi download

A few weeks back my android device was infected with some adware.This adware automatically opens the play store and installs random apps.If i uninstall the app,it immediately opens the play store again.This wasnt the first time an adware was installed on my device without my knowledge.I simply uninstall the adware from my device whenever this situation occurred however this was different.The adware had installed itself as a system app so it couldnt be uninstalled as my device wasnt rooted.I tried several antiviruses from the play store but they all required root permission.

I finally did root my device and when i ran antivirus scan it found 3 viruses but strangely enough it couldnt remove any of them.The antivirus took me to the uninstall screen and it said uninstall finished but the virus was still showing in the detected list.I managed to remove 2 of the viruses by going to their apps folder in system and uninstalling from their but this one pesky virus wont go away.Its stored under system/priv-app/ as rt.apk and while uninstalling, its name is listed as prevail.

Any tips?