Hello,
I had the exact same problem with ads constantly popping up. In my case, this adware is located in the system partition. The only thing I can think of to get rid of it is by reflashing the ROM. Unfortunately for me, it’s incredibly difficult to find a ROM for my phone. Since I couldn’t delete the adware, I disabled it. If you can’t delete, disable is the next best solution.
In my case, the adware app is called “ad-surface”. If you don’t have this adware, here’s the links I used as reference for other possible solutions:
https://android.stackexchange.com/q...app-is-causing-popups-not-in-notification-bar.
https://forums.androidcentral.com/g...random-apps-keep-installing-themselves-3.html (This one refers to malware and how to get rid of it starting on the 2nd page. Found it to be informative.)
On a side note, I heard other people having ads from their app “Featured Apps”. I didn’t have ads coming from it. However, I disabled it to maximize my phone’s performance.
Here’s my solution that worked for me:
1) Go to Settings.
2) Next, go to Apps.
3) Once there, look for the 3 vertical dots on the top, right corner. Select it.
4) Next, select the option “Show system”.
5) Scroll down to “ad-surface” and select it.
Next, select Disable, and for good measure (optional), I select “Force stop”. However, need to Force stop every time restart phone.
6) Optional (for good measure), beneath Disable, select Storage, and then “Cleared data” and “Clear cache”.
7) Optional, beneath Storage, select Data usage, and then press on the button for “Background data” to disable it.
8) Optional, beneath Data usage, select Notifications, and then press on the button for “Block all” to enable it.
9) Optional, finally, beneath Notifications, select “Draw over other apps”, and then press on the button “Permit drawing over other apps” to disable it.
Good luck! Hopefully, this works for you too!