I flashed the coordinator firmware in to my CC2531 dongle (CC2531ZNP-Prod.hex).
Then I flashed the router firmware in ti my two other CC2531 dongle (router-cc2531-std.hex)
I installed last versione of zigbee2mqtt v. 1.9.0
I restarted my Hassio v. 0.104.2
In the log of zigbee2mqtt I view that coordinator was recognized…
I switch on join command
I pressed > 5 sec SW2 of CC2531 router… but it blinks one time a second and do not pair with coordinator