Hi Phil M , I have a sk1 and a kind of that problem ...
It was working normal , and suddenly when I turn it on , the display shows the welcome message " HAMOND SK1 gloriou's voices " for about 5 min , and then when finally starts, everything works normal but it doesn't have any sound in any output .
I tried to restor to the factory settings , but doesn't help , and also I tried to upgrade a latest version but it shows me don't need to upgrade ( or something ) so it doesn't help too .
I would like to downgrade , as you said , but don't know how to get the old software . Is possible to download for the Hammond page ? Or is possible that you can send me ?
Thank you for the tips !