760GM-HDV MB SATA support

As the subject says, it's an Asrock 760GM-HDV motherboard. AMD FX-4300 cpu, although I don't think that matters... and it's BIOS version 1.10.   There are 4 SATA ports but they are not identical; I can't get the BIOS to recognize a SATA hard disk or a SATA CDROM drive on ports 3 or 4. Both drives work fine on ports 1 or 2. So... why not just use the ports that work?   Well, I want to have two HDD and one CDROM devices and that means one of them has to be on port 3 (or 4). Yes, in the BIOS settings for SATAII_3 (for example) I've chosen "type = CD/DVD" to no avail. And, of course, "type = AUTO" doesn't work either.

Different topic (maybe...?) There seems to be a BIOS version 1.20 available. I have downoaded that, 760GM-HDV(1.20)ROM.zip, and unzipped it to 760GHDV1.20 onto a flash drive. The "Instant Flash" option in BIOS finds the USB device but reports "no BIOS files found." (I have even tried renaming it to 760GMHDV1.20 in the hope that the file name had to match the MB model. Didn't help.)

So, really two questions: is there a work-around to the ports 3 and 4 not recognizing genuine SATA devices? And, is it worth trying to flash the 1.20 BIOS version? And if that is the case, How to do it?

Thanks.