Thanks for that hint. I use openhabian So it should work fine 
@Chrishab Shouldnât you be able to plug the 2nd router into another Linux/Windows machine to join it with the coordinator? Many people donât have an extra PI around, but they should have another desktop. My second CC2531 is coming, so I guess I will learn soon.
Nice! My current system is working perfectly but for a few bucks this is certainly worth a try, just for fun.
As I have no mesh/router zigbee network experience, do you notice any delays when one or multiple hops are necessary between OH and receiver?
I havenât got the router up and running yet; my 2nd sniffer is still on the way.
@yfaway Yes, i had issues in the beginning adding the routers to my Zigbee network (no idea why) which is why I used Zigbee2mqtt. However, I have started from scratch (luckily my Zigbee network is not too large yet) as I ran into issues.
In the meantime the router firmware also got updated. I re-flashed my routers with the latest version and now even openHAB was able to find the routers. You could even use a USB charger to power the device. No Linux/Windows machine necessary (except for flashing).
@bartsnijder: so far I havenât noticed any large delays. In regards to multiple hops: I don"t even think thatâs possible. As far as I understood the documentation each router needs to have direct âcontactâ to the controller. So a setup like controller >> router 1 >> router 2 doe snot seem to be possible.
Hi all,
I was able to get a CC2531 with Zigbee2MQTT working.
One question come in my mind. It is possible to bind the CC2531 to Zigbee2mqtt AND the OH binding twice?
I want to use my Xiaomi things and Osram Lights with only one coordinator (the CC2531)
Or do I have to bind every zigbee thing to Zigbee2MQTT and with this to OH2?!
Hope you are able to understand what I mean? 
That the way.
The CC2531 canât run 2 firmwares at once.
Okay and what is if I have installed two zigbee coordinators on one PI Would this be feasable?
Yes, absolutely.
What is the problem with zigbee2mqtt controlling all of it?
A CC2531 coordinator can support up to 15 devices (including routers) connected to it. This is due to the limited memory on the CC2531. That means you would only need more than one coordinator if you have more than 15 devices and routers.
I just received the second CC2531 sniffer yesterday. I flashed the router firmware and it was able to connect to the coordinator pretty quickly. I had a Xiaomi temperature sensor that has stopped working for a while, likely due to range issue. I just left it there since I was too lazy to re-pair it. And suddenly this morning it comes back alive again, thanks to the router. So for all of you out there having intermittent issues with the Zigbee devices, just throw in one or more routers, and everything should work a lot more reliable.
Note that you donât pair your device with the router. You still have to pair it with the coordinator. Depends on the range, the device might go directly to the coordinator. Having a router doesnât increase the # of devices the coordinator can support; it actually decreases by one I think, as the router is counted as one from the coordinator perspective.
@vzorglub
It is only a bit more effort to get it working
With a direct bind to OH it would a bit easier to manage it I guess, but currently I have not that much expierence on dealing with MQTT on OH2
Time to learn. MQTT is one on the IOT main protocols and itâs quite easy to use once you get the basics.
I tried the Xiaomi / Aqara temperature and pressure sensor with the coordinator QIVICON Telegesis and it works with the Zigbee binding without a Xiaomi gateway and without installing zigbee2mqtt. Unfortunately I had already ordered CC2531 which will arrive in the next few days. 