"I found a firmware but it was for mks plus !"
I can't see how you can recover that one, unless you get a new (or original) firmware and/or control board from your supplier.
As for the Infini, it doesn't sound to me like an issue that a firmware update would fix, or would be necessary for. Infinis are complex to set up; my guess is that you have incorrect settings. I don't know enough about Infinis to offer help on that. Perhaps post a question on a suitable forum to see if other Infini owners can help.