I have so far been unsuccessful at getting Jay Moseley's MVS 3.8 installation procedure to work reliably on a Raspberry Pi. This is almost certainly not the fault of his procedure, but possibly due to the way in which I have built Hercules or possibly due to some issue with Hercules on the Raspberry Pi. However, building the DASD images on another computer and then copying them to the Pi does seem to work, and can speed up the installation process considerably (depending on what the other computer is).