OK , after a few week of trying different things , here's what works on my 2020 A4 , use at your own risk :S
This is what I did ,( with weeks in between ).
Initially made adaptations to module 5F - (Having found out what I have today , I'm not even sure these need to be made , these were things quoted for previous models of Audi (Non MIB3 ) A3 / A7 / A6 , and some of the settings in the other modules contradict values in this module, so not even sure it is doing any thing with these values )
I think this should work with A4/S4 , A5/S5 MIB3 models.
Before doing this delete the phone pairing in bluetooth and CarPlay in Audi interface (long hold and delete ) , I also removed the car from my phone bluetooth (again maybe not necessary)
Make sure your bonnet / Hood is up/open for changes to take effect .
MODULE 5F
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Adaptation
Control unit: 5F Multimedia
Name: WLAN settings
Values:
5_ghz_wlan:
Old value: Off
New value: On
Mileage: 1691 km
Date: 2020-07-23 16:55
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Adaptation
Control unit: 5F Multimedia
Name: Smartphone configuration
Values:
Apple_car_play_wireless:
Old value: Off
New value: On
Mileage: 1691 km
Date: 2020-07-23 16:56
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Adaptation
Control unit: 5F Multimedia
Name: function_configuration_connectivity
Values:
Mirror_link:
Old value: Off
New value: On
Mileage: 1691 km
Date: 2020-07-23 16:59
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Adaptation
Control unit: 5F Multimedia
Name: function_configuration_connectivity
Values:
WIFI_Hotspot_5GHz:
Old value: Off
New value: On
Mileage: 1705 km
Date: 2020-07-24 17:01
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The following are new changes I found today , after scanning though all the available adaptations , these seem to have made the difference , and I now see the 5ghz network and wireless car play is working (seems too simple) .
MODULE 75 Telematics
Adaptation
Control unit: 75 Telematics
Name: Emergency call module and communication unit, configuration
Values:
WLAN 5GHz:
Old value: Off
New value: On
Mileage: 1965 km
Date: 2020-08-14 14:54
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Adaptation
Control unit: 75 Telematics
Name: Smartphone configuration
Values:
Apple CarPlay Wireless:
Old value: Off
New value: On
Mileage: 1965 km
Date: 2020-08-14 14:53
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Now reboot the MMI , (Long hold on volume / power button , until the mmi starts up again )
Connect to the (hopefully) new SSID network / Hotspot YOURCAR_5ghz (enable hotspot in connection manager/wifi to see this)
Pair phone through Audi Smart phone interface bluetooth , it should as if you was to use Carplay
Let me know how it goes ..