I’ve tried resetting to factory defaults on several that displayed this error and it didn’t make a difference. I can downgrade them to firmware 541 without the error but upgrading generates this message.
I had a handful of terminals that were 569 and didn’t have this problem however the majority of the older terminals are 541. I don’t have a copy of the 569 build or 576. The only ones that I have are 541, 581 & 590.
Did trying an older image fix the issue for you? I’m having this same problem when I upgrade an S30 terminal to the 590 image. I currently have the 541 image on my older S30s which are having this problem.