When sending {"t": "scan"} request i got:
{"t":"dev","bc":"","catalog":"gree","series":"gree","model":"gree","lock":0,"vender":"1","mid":"60","name":"GR-Gcloud_60_0a_5ba3_EC","ver":"V3.2.M","mac":"9424b8fd5ba3","subCnt":6}
"subCnt":6 is number of indoor units.
Then sending request to get a list of units:
{"cid":"app","i":0,"pack":"Lmtc+jPqo5okmScSkppBww==","t":"subList","tcid":"9424b8fd5ba3","uid":0}
(pack with empty payload), "t":"subList" is the point.
The responce will be:
{"t":"subList","i":0,"c":6,"r":200,"list":[{"mac":"09c4a41d000000","mid":"6049"},{"mac":"352ea01d000000","mid":"6092"},{"mac":"655ea31d000000","mid":"6049"},{"mac":"0741a01d000000","mid":"6092"},{"mac":"21eda91c000000","mid":"604c"}]}
(Here i have something strange, i have 6 units, but list contain only 5, on phone app i see all 6 units)
And now if i send regular payload, but in "mac" i put internal unit mac adress, it works,
{"cols":["Pow"],"mac":"21eda91c000000","t":"status"}
i successfully got stats, powered on and off, changed temperature.
https://github.com/home-assistant/core/issues/122200