I have something like this working, or at least very close. I have Windows 7, 8.1, and 10 in x64 and x86, as well as MS-Dart 6.5, a hand-modified Falcon4 UBCD, and AOMEI's PE Builder 1.5 booting from a single 32 gb flash drive. The "at least, very close" part, is that 7 & 8.1 installers use a generic winpe.wim in place of boot.wim. By default, this drops me into a command prompt. I haven't tested this next part yet, but if I did it correctly, I believe I've integrated an automatic installer for drivers from driverpacks.net and a multi-oem customizer tool. Note that I did not write or create any of these separate tools - I am only integrating them together. Back to the topic at hand, and as I was saying, 7 and 8.1 installers drop me to a command prompt inside the RAM disk for winpe.wim. From there, I am able to change drive and directory and run the correct setup.exe for the system at hand. I started out using Windows 10's Media Creation tool to create a bootable USB drive, and added more stuff from there. I have no doubt I'm going to get a flood of more questions on this in the near future. I'm happy to help to the extent I'm able. --Aaron