There's a small boot utility to test physical memory from PassMark and I'd wish to add this tool to Windows 10 boot menu, but unfortunatelly the format in which Passmark delivers this tool (IMG) is so nonstandard that I'm not able to convert it to anything usable for Microsoft's boot manager. At least converting it to proper ISO and adding it to BCD store via EasyBCD would work, but the problem is that the IMG architecture is so strange that the resulting ISO has unrecognizable structure.
By using OSFmount I'm able to mount this image either as physical drive or logical one of the two contained partitions (2x FAT 256MB), then saving the virtual drive to ISO works but as I mentioned, it's not readable.
Any clue how to handle this really weird image for MS bootmgr would be very appreciated!