after upgrading my MiMix from 10.1.1 to 10.2.1 the Wifi only sees 5GHz WiFi networks, no longer 2.4GHz ones...
I've done an upgrade (dirty flash) over the perfectly working 10.1.1
Is it just my Mix, or a common problem?
I am on the latest update as well and I noticed that in my office wifi is on Channel Width 20 (2.4) and Channel Width 80 (5) and the mobile is not seeing the 2.4 GHz on HT20. Whereas the 2nd WiFi is on both Channel Width 40 and its showing so mean in the latest update Channel Width 20 is having issues.
If you live in the EU, you can try to manually edit build.prop and change ro.miui.wifi.region from GB to your country code. That might prevent you from using 5GHz hotspot (or might not), but other than that you should be able to see all supported channels in your country.
The 5Ghz wifi is going to be basically unusable if everyone implements the new rules correctly, like Huawei seems to have done.
There is an article on MIUI forum about how 5GHz wifi has interfered with European weather radar.
My pocket router will spend a whole minute checking frequencies every time it thinks it has seen a weather radar signal, before it starts working again.
This is what every hotspot is supposed to do, apparently.
However, the 2.4Ghz wifi should work as before, as far as I have seen.
Thanks everyone, problem solved!
My 2.4GHz band was forced to channel 13, and apparently the new stable ROM can't use ch. 13 (it was supported until the previous stable, 10.1.1)
As soon as I've set the access point to auto channel the Mix saw the 2.4GHz band again.