SD with Windows only bootable in USB Adapter

Discussion in 'Windows, Linux & Others on the Mac' started by Beardyman, Aug 6, 2013.

  1. Beardyman macrumors newbie

    Joined:
    Aug 6, 2013
    #1
    Hello guys,

    I recently purchased a SanDisk Extreme 64GB Micro SD card which is amazingly fast, at least for an SD card. Write speeds are around 60 MB/s and read speeds are even faster at around 90 MB/s. This isn't any slower than a typical 5400 rpm laptop hard drive, and access times doubtlessly are better on the sd as there are no moving parts. So I wondered if I could use the SD as a volume for installing and booting Windows 8 on my MacBook Pro with Retina Display. I use the 15 inch model and don't want to have Windows on the internal SSD, so I figured the SD would be perfect for that.

    The MacBook has no Micro SD slot so I plugged the card into a small USB adapter. Using this adapter the card is recognised just like a USB thumb drive. Using a Parallels VM it was a piece of cake to install Windows 8 onto the USB drive using tools from the WAIK. If you want to know how to do this, just search for "Windows to go". Next thing I did was trying to boot nativly from the drive. Pressing "alt" during boot brought up the boot menu and it also displayed the SD card as a USB volume (still in the USB adapter). Suprisingly, Windows 8 booted up just fine and everything went as I wanted it to. Great so far!

    The USB adapter I am using sticks out a little and obviously it blocks a USB port. Yesterday I finally was able to get a Nifty Drive. If you haven't heard, the Nifty Drive is a Micro SD to SD adapter that is shorter than a normal SD card. This way it fits perfectly in the MacBook and doesn't stick out at all. Perfect if you want to use your Micro SD as a permanent storage upgrade.

    Without any hesetation I put my Micro SD into the Nifty Drive and into my MacBook. On boot, the first problem appeared. The SD card doesn't show up in the bootloader so i can't choose to boot from it. Maybe the Micro SD had been damaged? No, using the USB Adapter it still boots fine. After reading some stuff on the internet i decided to try rEFIt. I created a small partition on my internal SSD and installed rEFIt onto it. With the SD card in the SD slot I booted the Mac while holding down "alt". The bootloader appeared once again and showed my OS X partition and the rEFIt partition. After choosing rEFIt the rEFIt bootmenu comes up just fine and it even shows my SD card! Great! But wait, there still is a problem. Trying to boot from it through rEFIt just displays an error message after a while, telling me, that the bootloader is missing. How can this be? Using the USB adapter everything everything still works as it is supposed to.

    Some additional information:
    - SD card uses a MBR
    - One partition on the SD formatted in NTFS
    - 15" MacBook Pro with Retina Display (Mid 2012)
    - Windows 8 Enterprise x64

    Can anybody tell me, why this is not working? I would love to find a solution to the problem!

    Greetings from Germany
     
  2. alexrmc92 macrumors regular

    Joined:
    Feb 7, 2013
    #2
    The EFI firmware will not boot from the SD port. rEFit is no longer developed, you can try rEFInd but it doesn't have a boot loader build in so windows may not load anyways as you said it is setup to boot from MBR.

    I just made this public, if you want we can try to work out a way to boot windows with it. I haven't tried booting windows in it yet.

    http://forums.macrumors.com/showthread.php?t=1619404
     
  3. iMacDragon macrumors 65816

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #3
    Most likely because the SD card slot is on PCIe bus not USB, so windows would need correct drivers at boot time to be able to boot off it anyway.
     
  4. alexrmc92 macrumors regular

    Joined:
    Feb 7, 2013
    #4
    Apple connects the SD slot to the USB bus, but the EFI firmware was designed not to boot from the SD slot.
     
  5. iMacDragon macrumors 65816

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #5
    On both macs I've had with SD readers they've been connected to a 1x pcie lane

    "Built in SD Card Reader:

    Vendor ID: 0x14e4
    Device ID: 0x16bc
    Subsystem Vendor ID: 0x14e4
    Subsystem ID: 0x96bc
    Revision: 0x0010
    Link Width: x1
    Link Speed: 2.5 GT/s
    "

    That's not a usb connection, that's a pcie one. also it doesn't show up in the USB tree, unlike keyboard/trackpad/camera.
     
  6. Beardyman thread starter macrumors newbie

    Joined:
    Aug 6, 2013
    #6
    The SD Card Readers in the current MacBook Pros (not in the Air) are connected via pcie. Also, the EFI Firmware can boot of the SD without a problem, installing OS X is a piece of cake.

    You might be right about the pcie drivers though. Do you know if there is any way to include those drivers with windows? Maybe the needed drivers can be extracted out of Apples Bootcamp drivers.
     
  7. iMacDragon macrumors 65816

    iMacDragon

    Joined:
    Oct 18, 2008
    Location:
    UK
    #7
    Fair enough, I've only had Pro's admittedly.

    I think drivers that enable windows to boot off a device are a little different to the normal drivers windows use, and apple won't supply those.

    Though third party ones from the actual chip vendor might be available, I've not investigated it.

    I have installed Mac OS myself from SD so I know that is certainly possible.
     
  8. alexrmc92 macrumors regular

    Joined:
    Feb 7, 2013
    #8

    This must only be the case with PCIe SD readers then, as i have a USB reader any my mac refuses to boot from it. It won't even show when holding alt during boot up.
     
  9. Beardyman thread starter macrumors newbie

    Joined:
    Aug 6, 2013
    #9
    Maybe the SD card is not blessed correctly then or something else is wrong. I have booted OS X from an SD card in a MacBook Air myself. It works just like booting from a USB drive which is obvious, as the SD card reader is connected through a USB bus.
     
  10. Dalton63841 macrumors 65816

    Dalton63841

    Joined:
    Nov 27, 2010
    Location:
    SEMO, USA
    #10
    Booting OS X from an SD card != Booting Windows from an SD card. Unfortunately it will not work like that. I've had my rounds trying to make that work.
     
  11. alexrmc92 macrumors regular

    Joined:
    Feb 7, 2013
    #11
    I should have clarified, OS X will boot fine from SD, but not windows. It's as if the firmware only sees HFS+ partitions on SD cards when booting. I spent a few hours trying to get it to work before i just used a usb adapter.
     

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