I'm creating a multiboot usb drive with several distros. But I also want to add Hirens Boot CD which runs a Windows Preinstalled Environment. The problem is that Hirens is not included in Yumi, the only options is to add Hirens Bios only, which doesn't include the GUI version. So I created a separate usb with Hirens only. so now I have the structure created. and the only thing is now to added to my multiboot usb created with Yumi. But I don't know which file should be called when that option gets selected during boot. I know I have to edit some menu file, probably some file with extions lst or cfg, but I don't know what files/folders should I copy. I don't need a bootloader b/c the other usb already has it installed... if anyone can help with this. appreciated

I thought Yumi could boot a straight iso image without converting it?
Since Hirens is using WinPE, it is not as easy to manipulate booting as a Linux distro, so coping it from one USB to Yumi will not work. I think I was able to install it on my Multisystem USB as just a iso file some time ago. Multisystem is the thing as Yumi but for Linux.

If it is WinPE then maybe this. https://geekvisit.com/multiboot-usb-...ndows-bcd/amp/

See post # 3 at the link below at the Ubuntu forums.

https://ubuntuforums.org/showthread.php?t=2409935