<![CDATA[Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM?]]>I'm pretty sure the answer is no, and that the VM needs to start new with UEFI and with vTPM, but just looking for confirmation.

TIA.

]]>https://xcp-ng.org/forum/topic/10457/is-it-possible-to-convert-a-bios-to-uefi-and-introduce-vtpm-into-an-existing-vmRSS for NodeSat, 12 Sep 2026 17:48:45 GMTWed, 12 Feb 2025 21:36:06 GMT60<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Tue, 16 Sep 2025 07:18:35 GMT]]>@Berrick Ah cool, I was anticipating that doing it live would've caused boot issues but I think I've just got a bug in my head about how it actually works, I'm conflating two separate things based on an incorrect interpretation of a previous experience I had once with XCP.

Thanks!

]]>https://xcp-ng.org/forum/post/97414https://xcp-ng.org/forum/post/97414Tue, 16 Sep 2025 07:18:35 GMT<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Mon, 15 Sep 2025 16:19:58 GMT]]>@DustyArmstrong
From memory I did this live.

I did have backups before attempting, though and the VM wasn't super critical.

]]>https://xcp-ng.org/forum/post/97391https://xcp-ng.org/forum/post/97391Mon, 15 Sep 2025 16:19:58 GMT<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Mon, 15 Sep 2025 13:42:38 GMT]]>@Berrick Thanks for your post. Did you export the VHD, run the commands against it then re-import it, or did you just do this on the live VM? Presumably you exported and re-imported like Andrew did. I think I understand what the process would be either way, but it would still be good to confirm with someone who already had success what your sum total steps were.

]]>https://xcp-ng.org/forum/post/97375https://xcp-ng.org/forum/post/97375Mon, 15 Sep 2025 13:42:38 GMT<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Sun, 07 Sep 2025 16:38:25 GMT]]>@Andrew said in Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM?:

I have not converted windows as I normally started newer versions as UEFI and older version work better with BIOS

For peeps that stumble on this post looking for answers, the answer is yes you can for Windows.

You can use the built in Windows mbr2gpt program to do so. However, things to consider before attempting are?

  • You can only have 3 partitions on the C driver. This is due to MBR only supporting 4.
    the 4th partition will be used during conversion

  • it also has to shrink some space from the end of the drive

  • You might have to move the recovery partition if it is at the end of the disk

Basic steps are, to first run the command below. This will tell you if conversion should works

mbr2gpt /validate /allowfullos

Then the following to start the conversion

mbr2gpt /convert /allowfullos

Hope it helps someone

]]>https://xcp-ng.org/forum/post/97109https://xcp-ng.org/forum/post/97109Sun, 07 Sep 2025 16:38:25 GMT<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Thu, 13 Feb 2025 12:59:32 GMT]]>@Andrew To me the summary answer is no, ha. The content of this system is nothing super important. So replacing it new would be the quicker approach.

]]>https://xcp-ng.org/forum/post/89638https://xcp-ng.org/forum/post/89638Thu, 13 Feb 2025 12:59:32 GMT<![CDATA[Reply to Is it possible to convert a BIOS to UEFI and introduce vTPM into an existing VM? on Wed, 12 Feb 2025 22:40:06 GMT]]>@DustinB The answer is yes, you can, I have.

I have changed modern Linux form BIOS to boot as UEFI. All I had to do was change to GPT, add a ESP/EFI boot partition, change the OS partition mounting, and install the needed EFI boot files. Also update the OS to know it's now a EFI boot setup so the OS updates boot files correctly (a GRUB package change). Then I can set the VM to be UEFI boot... It was not an automated process and I did it as an off-line procedure (not booting the OS I was changing).

UEFI VMs boot quicker than BIOS VMs.

I have not converted windows as I normally started newer versions as UEFI and older version work better with BIOS.

]]>https://xcp-ng.org/forum/post/89628https://xcp-ng.org/forum/post/89628Wed, 12 Feb 2025 22:40:06 GMT