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Dual boot Windows 8 & Windows 7

    Question

  • I made a copy with bcdedit /copy {current} -d "Windows 7"

    and set the device + osdevice pointing to my Windows 7 volume.

    At the next reboot there's an option to choose the OS that should be loaded,

    but AFTER booting up nearly the whole Windows 8.

    When I select Windows 7 the machine reboots completely and start Windows 7.

    That way we're loosing time with the whole Windows 8 boot process + the reboot.

     

    Is there a more effective way to select the OS at Startup (without loading so much Windows 8)?

    A binary filecompare between bootmgr(win7) & bootmgr(win8) shows a lot of differences.





    • Edited by dynamind Wednesday, September 14, 2011 8:36 PM
    Wednesday, September 14, 2011 7:36 PM

All replies

  • yes, install your own bootloader.  I wrote a similar answer to another user asking the same thing and here are the instructions I gave him:

     

    STEP 1: insert your windows 7 recovery disk and wait for it to boot into it

    STEP 2: hit "repair my computer" once the disk has booted

    STEP 3: hit more options, then command prompt

    STEP 4: type in command prompt: bootrec then, type bootrec\fix MBR

    STEP 5: type exit in the command prompt or click the x on it to close it

    STEP 6: reboot your PC, it MIGHT boot into windows 7 by default rather then presenting you with the option to boot however, it is then when you should use a 3rd party boot manager (my personal favorite is EasyBCD) from windows once it boots

    STEP 7: reboot once the boot manager settings have been applied

    STEP 8: repeat steps 1-7 if unsuccessful

     

    Hope that helped a little, the bootloader on windows 8 was made for simplicity, but, remember, this isn't the final release and that more improvements will come in time.

    Wednesday, September 14, 2011 9:01 PM
  •  

    thanks,

     

    but easyBCD is not a bootloader, it's an interface for bootmgr to easily manage the entries.

     

    I tried the steps you mentioned, but it leads to an infinite reboot of the windows 7 recovery console.

    bootmgr from windows 8 is loading different stages, the only thing that helps is a prebootloader like grub,

    so you can chainload any separate OS. BTW that's not as elegant as with windows 7's bootmgr.

    at the moment the problem is the filename similarity, cause the routine {bootmgr} loads the file bootmgr.

    seems like those two bootmgr files differ too much for a fast dual boot like with windows 7.

     

    I thought about copying over the windows 7 bootmgr to the windows 8 partition but will it work loading winload.exe?

    I'm a bit confused about this entry:

    custom:250000c2         1





    • Edited by dynamind Wednesday, September 14, 2011 10:29 PM
    Wednesday, September 14, 2011 10:16 PM
  • You can look at the following thread describing a Dual Boot with Windows Developer Preview.

    http://social.msdn.microsoft.com/Forums/en-US/windowsdeveloperpreviewgeneral/thread/6b7ee112-6580-44b7-b7b0-ec105d4508c6

     

    Let us know if you have any questions.


    Marilyn
    Monday, October 03, 2011 12:21 AM
    Moderator
  • Download and install Visual BCD Editor - it is a complete GUI implentation of bcdedit with some enhancements like automatic loader creation for all Windows versions after XP.

    1. Create element "DisplayBootMenu" for {bootmgr} with value set to 'true'.

    2. Set default boot entry to be Windows 7.

    With these settings on my computer I cannot make a difference (on the user level) if I am using Windows 7 or Windows 8 bootmgr.

    Windows 7 boot manager cannot boot Windows 8.

    The bootmgr in control should be always the latest bootmgr in a dual or multi boot system as earlier boot managers do not have the knowledge and cannot load later Windows versions.

    Addition:

    custom:250000c2 1 - from another thread is for RE GUI, undocumented - seems to be of enumeration type.

    • Proposed as answer by BoYans Monday, February 27, 2012 9:12 AM
    • Edited by BoYans Monday, February 27, 2012 9:17 AM added explanation for custom:250000c2
    Monday, February 27, 2012 9:11 AM