It's the Zigbee coordinator USB stick firmware :
which I find strange as a requirement "....In order for this device to work" And these updates are dated November 2021, which is relatively soon.. My CC2531 stick was purchased before this date and I have not updated the firmware, but I just realize I have used Z2M and ZHA only with the older models Xiaomi RTCGQ11LM, not the newer T1 series.
There is something very interesting that I found while searching for info for the new Aqara motion sensors. The original documents are here and here, Although these notes mention Xiaomi, it may be true also for Aqara branded sensors... I have copied the text below:
Difficult pairing
To pair the sensor it needs to be reset first, by pressing the pin-hole button for 10 seconds.
Then after starting sensor search, press the button again until the LED blinks. Finally continuously press the button every 2 seconds until joining is confirmed.
Sticky Parents
Almost all Xiaomi end-devices stick to their parent after pairing. The parent is the device which repeats the signal, it can be a router or the coordinator.
Once a parent is cut from power or otherwise lost, the end-device won't automatically search for a new parent and appears to be offline.
→ Best practice for pairing is therefore to pair the device at the place where it's gonna be installed to force it to select a good parent. It's also advisable to power off all routers which aren't powered all the time, so that they aren't considered as parent when pairing.
