One of the memebers here recently bought two eg4 12000xp inverters and one of them has a 60hz hum. EG4 worked with him on the phone and wanted him to run a new neutral wire to each inverter to test for ground loops (I assume). When that didn't work, they remotely upgraded his firmware and finally told him they'd send him a new inverter and a shipping label for the old one. They will send a truck to get the inverter from him.

Folks, every manufacturer / business stumbles, it is expected. The tell is how they handle the boo boo. EG4 passed this with flying colors.