I wanted to root my tablet and installed a rootkit. Soon thereafter I realized that besides giving me root access, the rootkit was also uploading all my files and settings to some unknown place.
To get rid of the rootkit, I first decided to perform a factory reset via Android's menu. Upon completion, the rootkit application was still there! So I decided to re-flash the stock ROM using adb. This time, the rootkit was not visible in the application list anymore.
Is flashing the ROM sufficient to get completely rid of the rootkit/malware, or might it still be hiding somewhere? What else can I do to make sure future uses of my tablet are safe?
Note: my question here is not about the consequences of this breach. I believe that the leaked information is not (too) critical. I just want to ensure that I have a clean and safe tablet from now on.
I read this other question, it but does not give an answer about whether flashing the ROM will completely remove any malware and backdoor.