> the source of confusion: the freely available ROM updates. [...] it might be a good
> mid-term measure of course to create an alternative solution in WinUAE for initializing
> the emulated Cyberstorm turboboard (given that the actual content of the ROM isn't
> really needed without the physical board)

Apparently, such alternative solution isn't even needed as the ROM updates contain everything needed to create a full ROM file:

http://eab.abime.net/showpost.php?p=1118089