windows qemu-img fails to convert vhdx, assertion failure

When attempting to convert Microsoft's 10X emulator image (19563) vhdx [1], qemu-img terminates abruptly with an assertion failure. (Newer versions of the vhdx exhibit the same issue.)

Tested with qemu-img.exe --version
qemu-img version 4.2.50 (v4.2.0-676-g3a63b24a1b-dirty)

Possibly related: 1719870

Partial Powershell cmdlet output:

PS> Get-Vhd flash.vhdx

VhdFormat               : VHDX
VhdType                 : Dynamic
FileSize                : 8365539328
Size                    : 137438953472
MinimumSize             : 137438953472
LogicalSectorSize       : 4096
PhysicalSectorSize      : 4096
BlockSize               : 1048576
ParentPath              :
DiskIdentifier          : 7BE7C459-AE5D-451A-9368-05875120F702
FragmentationPercentage : 11
Alignment               : 1
Attached                : False
DiskNumber              :
IsPMEMCompatible        : False
AddressAbstractionType  : None
Number                  :


[1] https://1drv.ms/u/s!AnjdAnZZcu-GpNFK_-tcNAq_4Aug8w?e=5JB6s0

The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting older bugs to "Incomplete" now.

If you still think this bug report here is valid, then please switch
the state back to "New" within the next 60 days, otherwise this report
will be marked as "Expired". Or please mark it as "Fix Released" if
the problem has been solved with a newer version of QEMU already.

Thank you and sorry for the inconvenience.


Still a bug, resetting status per new bug tracker guidance.

Also, re-tested with  v6.0.0-11869-g800a25ea45-dirty. Results in error:
ERROR:../../../util/oslib-win32.c:61:qemu_try_memalign: assertion failed: (is_power_of_2(alignment))



This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/250