Don't get your hopes up
Let's hope POS makers are all taking notes
Having worked in this sector, I can assure you that the market is full of scruffy, poorly understood, dubiously secure software that lives on from sequential acquisitions, used by retailers that you'd assume would know better. I know that some of the software potentially in the frame here has been acquired five times over, at least once though a major insolvency and criminal investigation. What's the chance anybody now understands the design, knows the code, understands the implementations etc?
There's as much chance of this sort of legacy EPOS being secured as there is of Adobe making Flash secure. And whether you like it or not, you're using this software daily.