# Help re-enabling ATA Channels, Windows does not boot



## Yammit (Aug 3, 2012)

I was looking at my HP dv4's device manager under IDE ATA/ATAPI controllers and was checking whether dma was enabled or not for my ssd. Anyways, this was what I saw.

ATA Channel 0
ATA Channel 0

etc... ""

ATA Channel 6
ATA Channel 6

The secondary Channels from 1-6 had no devices listed in their channel properties, but the primary Channels did have the device type listed. They had dma enabled so I thought it was good. I made the mistake of assuming the secondary channels were not in use, so I disabled all the secondary channels and rebooted. My laptop would have a bsod flicker right after the Windows icon start up and then go to a black screen where it asked if I wanted to start the Windows Repair Utility or start windows normally. 

I ran the utility searching for automatic fixes and it came up with the result being unfixable. I did not have any Restore points on my HP laptop and had just installed a Crucial 256 GB ssd, which was working perfectly fine before.

Without reinstalling Windows 7 and all of the other programs I had loaded on there, is there a way to essentially re-enable those Secondary ATA Channels through unbuntu? My HP's bios has no option for switching from AHCI to IDE, which I was hoping would possibly reset the disable I did.

Also, are there any windows registry settings I can access in unbuntu to fix this problem regarding the disabled channels?

With an ubuntu boot usb, I am able to access all of the windows files on the ssd, so it is purely a windows device manager setting issue. Thanks for any help, but if there is not a quick fix, I can just back up anything I had recently installed and then re-install Win 7 x64 after re-formatting the ssd. That could be an easier fix.


TLDR... need to enable ATA secondary channels because I accidently disabled them in device manager while checking other settings. Windows will not boot anymore after making this mistake change. I have access to ubuntu and the Windows drive opens perfectly fine through that. Thanks for any help!


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## Yammit (Aug 3, 2012)

Uninstall IDE/ATA Channels To Fix DMA Issues

This is exactly what I essentially did, except instead of uninstalling the channels, I just disabled them.


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## JimE (Apr 16, 2009)

Uninstalling them tells Windows to remove the drivers. Upon reboot, Windows will reinstall the drivers.

Disabling them tells Windows to shut them off and not use them. You can try booting into Safe Mode. Or you can try using System Restore and going back to a time before you created the issue. Otherwise, a fresh OS install may be required.


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