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MP 3,1 - Can't boot Win7 from onboard SATA Ports


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Hi All,


I can't get Windows 7 to boot from my SSD connected to the onboard SATA ports (ODD ports) on my Early 2008 Mac Pro. Here are my specs:


Mac Pro 3,1 - Early 2008

2x Quad Core XEON


Intel 120GB 510 Series SSD

Intel 120GB 320 Series SSD

(I've disconnected all other drives, including the IDE SuperDrive)


Lion 10.7.1 is installed on the 510 Series Intel SSD, which is connected to one of the onboard SATA connectors, i.e. the connectors directly on the mainboard under the fan assembly. The drive is physically installed in the empty ODD 5.25" bay.

Windows 7 64-bit (SP1) installed on the 320 Series SSD, which is connected to one of the onboard SATA connectors, i.e. the connectors directly on the mainboard under the fan assembly. The drive is physically installed in the empty ODD 5.25" bay.

AHCI activated as per Ludachris/Johnsock approach, i.e. registry hack/MBR modification/Intel RST 10.1... installed with no error messages. Device manager indicates that AHCI is operating normally. Thanks to Ludachris and Johnsocks for their time and effort!!!


Problem: Windows 7 will only boot when the SSD is connected to one of the four drive bay SATA connectors. When connected to one of the onboard SATA connectors, I can select the Windows drive during boot up (when holding alt key), but after selecting it, after a few seconds, I get the "flashing folder" symbol on a grey screen. When connected to a drive bay SATA connector, booting to Windows (and AHCI) works fine. I want to use the 4 drive bay SATA connectors for storage and a time machine drive and the two onboard SATA connectors for the two boot drives, Lion and Windows 7.


Things I've tried:

- Booting from on an onboard port using the standard MS AHCI 1.0 driver, i.e. prior to installing Intel RST application

- Swapping the Lion and Window drives connected to the two onboard ports


I'd read on various forums that it's not possible to boot to Windows from the onboard SATA connectors on an Early 2008 MP, but I thought that installing AHCI would have addressed that issue.


Of course, the other option would be to install the Windows 7 SSD to a drive bay (using an adapter sled) and install the Lion SSD and a 3.5" HDD together into the unused ODD 5.25" bay (I still plan on using the SuperDrive). Would that even work? Is anyone aware of an adapter for installing a 2.5" SSD and a 3.5" HDD together in a 5.25" bay?


Thanks in advance for any help!

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I have the same MP as you do, I was never able to boot off of the 2 extra SATA ports and it will not be possible to do so unless you are using them to boot into OSX. The reason is this:

When you tell the EFI loader to boot an OS it determines if it is a natively supported OS that uses EFI to boot or if it needs to chain load the BIOS emulator to boot the OS. The boot process is as such:

1. Power on self test (completes with the gong noise)

2. You are then presented with either the boot camp selection screen or the rEFIt menu

3. You select the OS to boot

a. If EFI boot compatible OS the EFI takes over and boots the OS, in the case of the Mac the only EFI supported OS is Mac OSX

b. If BIOS boot compatible OS is detected the EFI options are disabled and the BIOS emulator takes over

4. If it was an EFI OS the SATA controller will remain in AHCI mode and boot the rest of the way into the OS.

5. If it was a BIOS OS the SATA controller will be immediately placed into IDE compatibility mode thereby disabling the 2 extra ports as an IDE controller can only handle 4 devices.

6. Our modification works because while the controller is in IDE mode it reads the bootloader on the hard drive that forces the controller back into AHCI mode and the boot picks up from there.


It _may_ be possible to have windows installed to a drive on the standard 4 ports to be the first boot device that will load the modified bootloader then you could use windows built in menu to chainload into the drive that is on the other 2 ports. I have not tested this and it may or may not work. Another possible method would be to use GRUB on the internal 4 drives to allow you to do the same method as this. The grub method may be better as you could setup a small 100MB partition on your main Mac OS drive that could be setup to boot windows from the other drives.


Good Luck.

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  • 1 month later...

Hi, I have a Mac Pro (early 2008 / 3,1) that is using the ODD Sata ports for two Blu-Ray burners. Is there a way to get these to be seen and mounted in Win7/64? I guess it seems "odd" they are not but then again they were labeled as such :-)

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