New MIUI 14 on Redmi K40 Pro +: unstable 5G and disconnections

[patch]

Hello,
there is a problem with 5G connection on Redmi K40 Pro+, every other packet is lagging on transit/receive. Just like when the connection has been jumping between LTE and 5G constantly, except the icon does not change and the connection is established, but "choking".
This leads to disconnections and lags.
Tested after clean install, both SIM card slots, different SIM cards and networks.

If set to LTE only, there is no lagging.
Please fix,
thanks

 

[KDR66]

Here MIUI 14.0.1 on Xiaomi 10T Pro, I have issues with 5G and after having read many things, it is pretty clear they changed something in their 4G/5G stack between 13 and 14. On my device, the issue is a bit different. I always have connectivity but it's sometimes extremely slow.

I discovered that disabling the data and reenabling it helped to get back to decent performance. Unfortunately, after a few minutes, it drops again to bad value. I tried the following test:

1. Disable the mobile data, wait 20 seconds, reenable it (5G)
2. Run a speedtest (I used "Speedcheck"): about 250 Mpbs and 70 Mbps.

3. Wait 15 minutes
4. Run the speedtest again: about 5 Mpbs in both directions, this is terrible

5. Disable mobile data, wait 20 seconds, reenable it
6. Speedtest -> back to decent values again.

Some hypothesis:
* Either "something" is introducing lag after a while in their implementation (timer, memory leak, etc.)
* Or 3G/4G/5G chipset is set to some kind of "low power" mode that prevents it from running at full speed and this mode is kept and can only be reset by changing mobile data state.
* Could be a mix of anything, like a bad flag at the low-level networking that caps it, but I really feel it's triggered by some timing.

Next step will be to analyze the logs