Specifically using this python package from github (which is excellent btw): I had implemented some of the software in this thread: Well I ordered mine from watts247 so I know I don't have a clone or some bootlegged hardware and I've been operating this thing for over a year. It's an ugly war between the original manufacturer (Voltronic Power), and the clone makers, and unfortunately people like you are getting caught in the crossfire. Don't bother attempting to source control boards from a legitimate importer they will ask for a serial number, and specifically won't help anyone with a clone. I assume that most clone manufacturers will have sorted this out by now. If that's the case, you need to get a new control board (it plugs in to the main board) for each machine from your supplier, with new firmware that solves this problem. Unfortunately, some clones aren't able to be updated at all. Not all models can be update in this manner. See Can I update my firmware, and to what? and Do I own a clone?.

But first check which model yours are a clone of, or you could brick the inverter. You might be able to update to factory firmware version 72.70, which doesn't have the error 90 check, or patched firmware version 72.70c or 73.00e. I believe it was designed to catch out clones who copy the firmware but not the bootloader. Error 90 (fault code 90) results from a mismatch between what is in the bootloader and what is in the rest of the firmware.

Infini inverter software