View Full Version : M4A785-M Will Not Boot From SATA in AHCI Mode

02-05-2011, 08:43 AM
I'm in the process of building out a new NAS system based on an M4A785-M and Athlon II x2 250 CPU.

After installing the OS (in this case OpenSolaris/Nexenta 3.0.1), the system reboots and hangs as though there are no boot devices. The system DOES NOT give me the "no boot devices" error that I would expect, it is just stuck with a blinking cursor. Note that the system itself is working: when booting from the install CD, all drives are visible to the OS, and can be installed accordingly.

This bug seems to be specific to leaving the IDE controllers in AHCI mode. If I switch them to IDE mode (the default), the system works and boots fine. I can also boot perfectly fine if I switch the controllers to RAID but leave all drives as "single drive". The problem only exists when ports 0-5 are all in AHCI mode.

Without AHCI I can't get to the SMART data from within the OS, and I lose some drive performance, so my strong preference is to find a way to get this working natively.

Has anyone seen this issue before? I'm running the latest BIOS, which came factory installed, but I confirmed it was up to date anyway.

Some more detail about the rig:

AMD Athlon II X2 250, NOT overclocked
4GB RAM (2x2)
160GB Seagate 7200.10 on SATA Port 0 (boot drive)
5x 2TB WD20EARS drives on SATA Ports 1-5
Using integrated graphics at 32MB
Not overclocking

02-05-2011, 10:49 AM
I'll follow this up with a note that you can work around the bug by disabling the legacy PATA interfaces (where my CDROM was connected in this case).

Still unsure if this is a motherboard issue or not - as first boot priority was given to the HD, so it should not have scanned or been blocking on the removable media.