I had the error 29 solve it with my technician of South Africa who installed our system... we have two inverters so if you switch off the one inverter the error moved to the othe r inverter, so he suggested to check my LAN cables even though it is new....so when I inserted a new LAN cable from the one inverter to the other one our problem has been solved....so maybe just check all your LAN cables if the fault is still there after a firmware update and so on....good luck