ZHA unknown shutter cluster issue

Hi
I have been struggling for hours, if not days with it, and I am resigned to beg for help.
I have paired an unknown_brand window shutter to Hass with CC2531/Zigbee2MQTT. This is done and the shutter command appears in HA / ZHA / Device Management where I have access to UP / DOWN arrows and even a ‘Position’ slider. But, any of the order I issue makes the shutter do a quick UP/DOWN move, like when it gets paired.

After enabling zigbee debug in Hass, here’s what I see:

2020-06-23 12:55:34 DEBUG (MainThread) [zigpy_cc.api] --> SREQ AF dataRequest tsn: 17 {'dstaddr': 14829, 'destendpoint': 1, 'srcendpoint': 1, 'clusterid': 8, 'transid': 18, 'options': 0, 'radius': 30, 'len': 6, 'data': b'\x01\x11\x04\x7f\x01\x00'}
2020-06-23 12:55:34 DEBUG (MainThread) [zigpy_cc.uart] Send: b'\xfe\x10$\x01\xed9\x01\x01\x08\x00\x12\x00\x1e\x06\x01\x11\x04\x7f\x01\x00\x89'

I also looked at Events when issuing an order:

{
    "event_type": "call_service",
    "data": {
        "domain": "zha",
        "service": "issue_zigbee_cluster_command",
        "service_data": {
            "ieee": "20:91:8a:00:00:0a:d9:19",
            "endpoint_id": 1,
            "cluster_id": 8,
            "cluster_type": "in",
            "command": 0,
            "command_type": "server"
        }
    },
    "origin": "LOCAL",
    "time_fired": "2020-06-23T22:10:08.339959+00:00",
    "context": {
        "id": "a273bec05fa54a5f8a87d768764b9983",
        "parent_id": null,
        "user_id": "c15de0256e894cb6bde5dc2b89f1e31d"
    }
}

and finally went to Cluster Commands, to the specific I want to use, but it fails with an error message “Wrong number of arguments for request, expected 2 argument(s)”.

Desperate I am. Questions I’d like to ask:

  • where can I see the Clusters’ code Hass has decided to use for my shutter, that remember are unknown ?
  • in Events, I don’t have ‘zha’ in the list of listeners, I had to use ‘*’ to get events for zha. Is it normal ?
  • for Cluster Commands, the error message complains it needs 2 parameters but I can only provide 1. Id is LevelControl 0x0008.

Any idea is welcome, and will be much appreciated.