What you can actually do is start up an emulated 1.3 environment with the encrypted ROM, use a ROM grabber from within the emulation, and voila - you'll have yourself an unencrypted ROM. You just need a way to get the file to your emulated 3.x environment - very easily done if you're using the Windows-directory-as-hard-drive filesystem, otherwise you'll need to "sneakernet" via floppy (ADF) or hard drive (HDF).
