After updating on Android 9, Wifi is very slow on all 2.4Ghz networks.
I localized the problem.With bluetooht turned on, wifi is slow.If the bluetooht is off then the speed is OK.
Same issue on my new 4.2. :(
Same on my 4.2 purchased this week. I also found that with the bluetooth turned off it fixed the problem. I also changed my modem channel from auto to 6 and that improved my wifi speed with the bluetooth turned on.
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