I just received this GBAN GB2530, from https://www.aliexpress.com/item/4000136938567.html .
I though maybe it was already flashed as router, or coordinator. I have an existing zigbee CC2531 flashed as coordinator and a few devices attached. Even making allow_join, the GB2530 did not rejoin. I tried the poweroff/on 3 times with 2 seconds of wait for repairing. I also tried as coordinator, with the instruction rtscts: false, but I got an error.