with latest svn, the following is now possible in MESS:

[Linked Image from mamedev.emulab.it]

given that it's not possible for carts to enable subslots, I had to create a new driver "snesst" which (similarly to snessfx) emulates a SNES+Sufami Base Cart and offers 2 cartslot to the user to mount the st carts

More screens

[Linked Image from mamedev.emulab.it] [Linked Image from mamedev.emulab.it]

[Linked Image from mamedev.emulab.it] [Linked Image from mamedev.emulab.it]

[Linked Image from mamedev.emulab.it] [Linked Image from mamedev.emulab.it]

some games work, some freeze at start.

also, mounting two carts is acknowledged by the emulated systems, e.g. because it warns you about carts inserted in the wrong slot

[Linked Image from mamedev.emulab.it]

and it sees both mounted carts

[Linked Image from mamedev.emulab.it]

but I don't think all data are read correctly...

I also had some work on the BS-X memory mapping which seemed promising (the CPU was able to reach reasonable code), but it turned out to be busted. so I threw it away and I left only the BS-X cartslot work. Due to device limitations, also the bsx unit is emulated with a separate driver: snesbsx offers two cartslots, the first for the base BS-X cart or for a compatible cart (like Same Game) and the second for the flash cart. However, the driver does nothing at the moment.