After spending much time checking jumpers, replacing ATA cables and experimenting with different BIOS options, I found the cause for the BIOS hanging after drive detection during POST. If I disable the pri ATA controller and enable the secondary controller, this is fine. If I enable the pri ATA controller and disable the secondary controller, this is also fine. If I enable both controllers, there is the hang. Further to the point, if I enable both controllers and disable the USB controller, I experience the hang. Specifically, to use both controllers I must have the USB controller enabled.
I am wondering if anyone has experience with this problem and knows whether the more recent 2.0g BIOS available from Gigabyte's website corrects this (what appears to be) bug. Gigabyte's website seems to document the latest BIOS as adding hard disk and CPU support, but there are probably other changes made that may or may not include a fix for this problem.
Thanks to anyone who can offer advise on this issue.