If you disable booting from the Marvell it should work just as it did before with the SATA controller as just a secondary controller rather than a primary boot controller.
I believe if you look in the BIOS for something like (in my case at least) Boot from SATA RAID or SCSI, you can pick SCSI and have it work.
This is going to be tricky though with that kind of a setup. Still if it becomes too much for you I'll gladly take those SCSI drives off your hands
