The solution changing the protocol back from ZIGBEE to MATTER on a H2 EU Plug is as follows.
-
Remove device from Matter-accessoires if already couplet before with HomeKit. Also remove from Aqara if runnin on ZIGBEE protocol.
-
Plug device in wal outlet, reset it (5 seconds). Unitll it blinks blue/purple
-
Start Aqara app, there you will see the device.
-
Aqara app asks which protocol you want. Choose MATTER and the app will ask if you want a protocol change.
-
Wait till the change is ready.
-
Device ready to be adder as a Matter/Thread device by scanning MATTER QR code.