Learning about bootmgr
Posted 22 November 2017 - 08:32 PM
Posted 23 November 2017 - 11:37 AM
I lost you after the second or third iteration
Also you do not detail HOW EXACTLY you "copied" this to that, when a volume (contents) is copied, the Registry (besides the BCD) Mounteddevices needs usually to be updated (or blanked and let the next boot re-populate them).
The symptoms (it depends on a number of factor) of a messed up MountedDevices key in the Registry are usually that of not being able to get to Winlgon, but it is perfectly possible that instead the "repair" is triggered.
Anyway this won't likely work:
I would have assumed a chain like MBR -> Bootmgr -> BCD store -> mount VHD on partition -> MBR (on vhd active primary part) -> Bootmgr -> BCD store -> \windows\system32\winload.exe
and I wonder how exactly you chainloaded the MBR inside the VHD (i.e. which exact BCDedit commands you used, or however what does your BCD(s) contain), there is no such thing (AFAIK, but the Windows 10 BOOTMGR may well be capable of that) as "mount VHD on partition" (BTW it has been reported that the Windows 10 BOOTMGR in recent versions lost the capability to chainload "legacy" bootsectors, possibly not related, still ...) .
But then you should have another kind of error.
Besides the complication of your attempt, you are also having a lot of added complcation "layers" (VHDX as opposed to plainer VHD's) and Hyper-V (which is known to have some queer behaviours), maybe unrelated:
The 100 Mb partition is the default if you install on a non-pre-partitioned hard disk (or virtual hard disk) as the standard install separates the "System" voume (what everyone else but MS would call "Boot") from the "Boot" volume (what everyone else but MS would call "System"), if you choose an already created primary partition "Boot" and "System" volumes are "merged" into one, this is "normal".
In the case of VHD booting, unless you use something like grub4dos that can mount in real mode the vhd (and not a vhdx) the "boot files" i.e. BOOTMGR and the \boot\BCD at least need to be outside the VHD, and the 100 Mb volume is probably the result of that, though I don't undestand what you mean by:
trying to make a non-native boot win7 vhd boot as if it were a native boot install
Try to simplify your question and better detail what you attempted to do, as is I cannot make head or tail of the problem .
Posted 23 November 2017 - 06:25 PM
How do you correct the bcd entries?
I corrected the BCD entries and tried to boot to this VM but it always comes up and says repairing installation and fails to boot.
Do you attach the vhd image at the host OS?
And run bcdedit next at host OS?
As for debug:
exract the bcd file to the host OS.
Attach the vhd image at the host OS
Run bcdedit to display the bcd settings.
Disconnect the vhd image next.
Run bcdedit to display the bcd settings again.
Connect a windows installtion ISO to the VM. Boot the VM from DVD.
Run diskpart.exe to view, attach the boot/system partition.
Run cmd.exe and change diretory to the bcd file.
Run bcdedit.exe to display the bcd settings at the hard disk.
Edited by cdob, 23 November 2017 - 06:26 PM.
Posted 27 November 2017 - 09:04 PM
OK, let me recreate the monster with the steps in greater detail so the process is clearer and get back to you.
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