Is there any way to copy the scsi.device 43 from WB3.9 and use it in WB3.1? (and without having to use the 3.1 ROM)
Yes. the Blizkick archive contains a program to split the RomUpdate file into single modules. Use it and copy scsi.device to Devs:.
Then get Thomas Richter's LoadModule and copy it to C:. Also copy the Reboot program from the Install3.1 disk into C:.
Finally add something like this to the beginning of your Startup-Sequence:
version scsi.device 43
if warn
loadmodule devs:scsi.device
reboot
endif
Don't forget to read the documentation of all mentioned archives before you start. Probably the LoadModule program contains a check and reboot option on its own.
However, are you sure the scsi.device V43 affects the Viper's driver at all ? AFAIK it is only for the internal IDE bus of the A3000, A4000, A1200 and A600. Perhaps the Viper's driver already is able to address more than 4GB. You might need NSDPatch though (to convert TD64 into NSD commands).
Bye,
Thomas