Windows 10: Can't native boot Hyper-V generation 2 vhdx

If I create a generation 1 VM I can native boot the vhdx by adding bcd entry. If I make a generation 2 VM it fails with "a required device isn't connected...0xc0000225". Pressing f8 for "Startup Settings" gives "The application or operating system couldn't be loaded because a required file is missing. File \Windows\system32\winload.efi. Error code 0xc0000225"

This is my BCD entry Code: Windows Boot Loader ------------------- identifier {default} device vhd=[D:]\Hyper-V\Windows-vm3\Virtual Hard Disks\Windows-vm3.vhdx path \WINDOWS\system32\winload.efi description Windows-vm3 locale en-US inherit {bootloadersettings} recoverysequence {2bd3faf9-6091-11e5-86c4-c3a22c898ce3} recoveryenabled Yes isolatedcontext Yes flightsigning Yes allowedinmemorysettings 0x15000075 osdevice vhd=[D:]\Hyper-V\Windows-vm3\Virtual Hard Disks\Windows-vm3.vhdx systemroot \WINDOWS resumeobject {2bd3faf2-6091-11e5-86c4-c3a22c898ce3} nx AlwaysOn bootmenupolicy Standard hypervisorlaunchtype Auto[/quote] and the Hyper-V definition (I've tried with and without secure boot, changing the boot order and removing the separate pagefile drive. It always works on Hyper-V will never boot on native boot.





Conversely if I install windows and turn off the VM before the first reboot I can boot it natively but Hyper-V will not boot (again complains of missing bootloader). The bootloader can't be repaired by bootrec, no valid windows installations are found.

Windows versions I'm using are 10 Pro build 10240 for host, build 10586 or 10240 for guest.

Does anyone know if it is possible to native boot a generation 2 VM vhdx and boot it through Hyper-V, the same as you can with generation 1?

:)

 

th2_release Enterprise 10586 fails

The only workaround really is to create a Hyper-V VM, attach your vhdx and then upgrade it.

You can't upgrade native boot vhdx.

 

th2_release Enterprise 10586 fails

It is the intended behavior according to here
Frequently Asked Questions: Virtual Hard Disks "Upgrading the operating system booted from a VHD. If you boot from a VHD, you cannot upgrade the Windows version in the VHD to a newer version."

You can both native boot and run the same vhdx in hyper-v (I do). If you have 2 installs on vhdx you can use each one to update the other... Otherwise with a normal install (not vhdx) on the same hardware you can install hyper-v, create a VM using the
existing vhdx and then upgrade it.

No idea the reason for the restriction but it has always been like that as far as I know.

 

How much HD space have you allotted. It needs to be able to expand to the full size during boot.

 

It's only 20GB maximum - I have space for it to expand to full size..

 

I would try at least 40gb, always worked for me in hyper-v at that size.

 

Thanks, I'll try that in a bit - I'm upgrading to 10586 at the moment... I found this as well which seems to say I'm making the bcd entry wrong...

Using VHD Native Boot with UEFI Firmware - bcdedit vs bcdboot - dai - Site Home - MSDN Blogs

 

That was it - bcd was created wrong method for UEFI vhdx.

In case it helps...

For generation 1:

• bcdedit /copy {default} /d "Boot from Foobar.vhdx"
• bcdedit /set {guid} device vhd="[D:]\VHDs\Foobar.vhdx" (replacing guid with the generated guid and D with the drive the vhdx is on)
• bcdedit /set {guid} osdevice vhd="[D:]\VHDs\Foobar.vhdx"
• bcdedit /set {guid} detecthal on

For generation 2:

• mount vhdx
• bcdboot F:\Windows (replacing F with the drive it vhdx is mounted to)
• bcdedit /set {default} description "Boot from Foobar.vhdx"

 

Glad you got it working right.