yes, this is not an easy job.

for now, vboot doesn't support this automatically, so you will have to do it by hand. We will try to add the support to MyOldPCs, and potentially provide a little utility to do the work.

If you boot the vhd on the same pc, it will boot to the real hd, if you don't change the disk signature.

you need to update all volumes in MountedDevices registry, search the binary value that matches the current signaure, then change them to the new signature.

the disk signature is the 4-byte integer located in offset 0x1B8 of the first sector of the hard disk.

Yaah, having integrated the Change Sig feature AND stand alone utility is excellent idea, since it matches the main purpose of using VHDs: for testing, deployment and similar tasks. Lets say one has several large app packages which may conflict with each other if installed together on a single system volume, or require different access privileges. Instead, one can prepare a basic OS install, Backup it and then Restore or Convert to VHD (or use a similar approach to prepare a basic System VHD). Then make a few copies of the VHD, save them on a single HD, boot and install onto each VHD a different package, say CAD or CAE app., or a set of specific drivers. He can later boot from any of these VHDs to run the required app on the same PC, or can use several of them at once by running in different VMs. Of course, he would need to change each VHD Sig before booting from it, so your utility would be handy.

the best approach would be to make vboot to update the disk id insitu if it detects a vhd with the same disk id as host disk. This is not difficult to do inside vboot.

this version will expire soon. Any new version? any news why I can't install XP in a VHD and why it overrides the host boot manager?

It's now several days past the 1.1 expiry. Can you please put an updated version up ASAP? Like today?