Android - A rather complex wifi issue (android tablet)

By looking at these two lines in logcat:

Could not set interface wlan0 flags (UP): Operation not permitted

WifiStateMachine: Driver start failed, retrying

I would say that the 4.4.2 ROM has a faulty/missing WiFi card driver (2nd line) without which you of course can't even start/scan/keep the WiFi connection (1st line).

As you have said, you haven't tried flashing it back to 4.2, but I strongly recommend to do so, at least to check if then the WiFi would work again.

If it then does work, that means the 4.4.2 ROM probably has faulty drivers or the permissions somehow changed so you don't have permission to turn WiFi on.

Depending on the outcome, you can either:

• Try to contact your OEM for a fix in 4.4.2
• Stay on 4.2 since you got no custom ROMs available
• MAYBE try to transfer drivers somehow from 4.2 into 4.4.2

I wouldn't rely much on the last option because of compatibility and changes in Android between versions, and besides that, it would require a lot of technical skill and knowledge + it could lead to potential hardware damage.