VirtualBox does not seem to do the job anymore (or at least not from GUI)

We can do this from Hyper-V (for example), but that does not allow this from GUI either.

The only way to change the boot sector and run some code on an Hyper-V VM is to use a VHD (not VHDX) with fixed size.

So, with Gui you can’t no longer create a VHD, so you need to do it in Powershell with (ex.):

   New-VHD D:\VM\Test.VHD -SizeBytes 1GB -Fixed
