BootCamp Partition Stuck in EFI Mode - can't set Brightness & Audio in Windows

Hi, I recently purchased WinClone 6 Basic after attempting to resize my Win 8.1 Bootcamp partition on a 2012 Macbook Pro (15") w. 512 GB Crucial SSD drive. Long story short, the resizing in Disk Utility screwed up my ability to boot into Windows. I created an image of the Win 8.1 partition, then tried to restore it, and only could get it to boot into Safe Mode after setting the Bootcamp partition to EFI Bootable in WinClone 6.

After this, I backed up all my critical files before people from my IT department at work decided to upgrade my Bootcamp parition to Windows 10. Now it boots into normal mode fine, but the display and audio drivers are not working right. I can’t adjust brightness, and audio doesn’t work at all, and in Device Manager in Windows 10, I see duplicate devices for the Audio and Display drivers. Disabling these doesn’t fix the issue, and I’ve also tried creating a Bootcamp Recovery Drive on USB, updating the Intel drivers, and running Windows Update. Nothing seems to clear the issue.

I’ve read online that this is related to the Bios being stuck in UEFI mode (Windows 10 thinks its running on a tablet, not a PC) When I go back to OSX and run Winclone 6 I try to set the Bootcamp partition back to Legacy Bios but this is the error I get.

“Could not mount /dev/disk0s5 Read/Write”

I’ve tried making the Bootcamp partition read/write, but I get the same error so I’m stuck. Is there anything I can do in WinClone or through the terminal or do I have to blow away the Bootcamp partition again and reinstall Windows? Please let me know

Best,

-Ed

Ed,

The Console should give better logging on what the issue is, but there might be a larger issue. If your boot camp partition is on disk0s5, it won’t boot legacy (it has to be in the first 4 partitions for legacy to work). It is possible that the disk identifiers are not sequential (which can happen when you create a new partition). If you reboot, and do a “diskuil list” in Terminal, you should see the correct identifiers.

As for the read/write issue, it is possible that the version of Windows that was installed doesn’t contain the files for legacy booting, but that is usually a different error message. Again, the console should show more info.

tim

Hi Tim, thanks for the quick reply. I’m afraid I’m a bit of a newb when it comes to sifting through the Console. I was able to run it from WinClone but didn’t see anything immediately actionable - is there a particular folder or location I should be looking inside for information?

As for the Terminal - here’s the output of the diskutil list

/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *500.1 GB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_HFS Macintosh HD 349.9 GB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
4: Microsoft Reserved 16.8 MB disk0s4
5: Microsoft Basic Data BOOTCAMP 149.3 GB disk0s5

Is there anything that looks wrong or off with this? Any recommendations or resources I should try?

Thank you again

Best,

-Ed

For legacy booting, the boot camp partition must be the last of the first 4 partitions, and yours is on partition 5. This can happen when you use Windows to create the partition instead of Boot Camp Assistant or Disk Utility.

tim

Hi Tim, here’s the thing - I didn’t use Windows to repartition the drive - I used Disk Utility.

Is there anyway I can change the ordering of the paritions via Terminal? Is the EFI partition necessary? Could it be deleted and would that restore the Bootcamp partition to the 4th slot?

Thanks!

Best,

-Ed

Ed,

After you used Disk Utility and installing Windows for the first time, did you do an “easy install” and let Windows partition the drive, or did you manually format the volume? If the former, that is probably when the recovery / boot partition was created.

I would stick to EFI booting and figure out the brightness issue. Try uninstalling the Apple related drivers in Device Manager and then reinstall the Boot Camp drivers.

tim