After flashing a custom ROM, there is a watermark in the top-right of the screen saying
xe6x9cxaaxe5x86x99xe5x85xa5google keyxe5x92x8ctee key
I've googled it and have tried several of the solutions suggested, but none have worked. Interestingly, most people get a slightly different variation of this message, in red.
I've removed "FactoryTest" from my phone, but do not have
com.mediatek.factorymode as some have suggested. I've messed around with my IMEI keys, this did not help. The message also still appears even with the SIM card removed.
Where on the phone could this be stored? My phone is rooted, so if I could locate the file responsible, I could easily delete it.
Download Minimal ADB and Fastboot on the computer
Plug in the phone into the computer, but keep the phone on
On the computer, open the terminal/command prompt
Enter these commands
adb devices adb shell pm list packages pm uninstall --user 0 com.mediatek.factorymode
Restart the phone and the watermark will be removed
You can kill/uninstall the sdrpmbFloat view service with root permissions. You should be able to go to Developer Options > Active Services to disable the service.