The Media Creation Tool for Windows 10 allows to create a multi architecture iso with both 32 and 64-bit version in the same image. It creates a separate x64 and x86 folder with the all of the contents of the 32 or 64-bit image, except it uses esd instead of install.wim. It uses BCD to choose which one to boot. It's possible to replace the esd with a wim file. Since the Media creation tool only creates Home or Pro, I replaced the esd with the wim of the Multiple edition version and it's working fine. So I tried to add more boot entries to the bcd, but it's not working. I renamed the x64 and x86 folder to x64en and x86en and edited the BCD to boot from the new location. The setup starts normally so it boots the correct boot.wim, but it stops with the missing driver error. What can be the problem? I tried to compare the media creation tool created image with the original, but could not find the difference.
Okay but what if you make two separate architecture AIOs, i.e., one for x86 and the other for x64 indexes. I believe these can be used to upgrade. I have tested that on Windows 7 AIOs but Win8.1/Win10.