So, I found two models of TCL phones in my warehouse(which both run Android 11). I extracted the APK for settings and tried to install it on my phone, the same thing happened to both: First, it didn't let me because it was a downgrade (not even sure why that's a downgrade.) The I did ADB install -d
which allows downgrade, but I got error that the signatures didn't match. And then out of curiosity, I tried to install one Smartphone's settings APK to the other smartphone, and it had the same error. I guess TCL signs all their APK's with different signature's (never had this issue with LG).