The latest Gandalf PE builds from WindowsMatters.com are (at the time of writing):
Gandalf’s Win10PE x64 Redstone build 14393 version 11-10-2016
Gandalf’s Win10PE x86 Redstone build 14393 version 11-07-2016
Using a partition image (UEFI+MBR)
You can add these to your E2B drive is to convert each ISO to a .imgPTN file using the MPI_FAT32 shortcut provided by the MPI Tool Kit. It should then MBR or UEFI-boot.
For the x64 ISO you will need to increase the suggested size to 5100MB.
For the x86 ISO you will need to increase the suggested size to 4300MB.
Tips: If you want as small a .imgPTN file as possible, extract the contents of the ISO to an empty folder on your desktop and then drag-and-drop the folder onto the MPI_FAT32 shortcut.
Use a file extension of .imgPTNauto so that it goes directly to the CSM menu and also add a timeout 3 line to the \menu.lst file inside the image.
Tips: If you want as small a .imgPTN file as possible, extract the contents of the ISO to an empty folder on your desktop and then drag-and-drop the folder onto the MPI_FAT32 shortcut.
Use a file extension of .imgPTNauto so that it goes directly to the CSM menu and also add a timeout 3 line to the \menu.lst file inside the image.
Direct MBR-boot from ISOs (MBR only)
E2B v1.90 and later supports direct booting of WinBuilder-based ISOs.
1. Ensure the .ISO file has no spaces in the file name
2. Keep the file extension as .ISO (do not use any other extension)
3. (optional) If you want to suppress the QRUN suggestion prompt, ensure the filename ends with the letter q or Q - e.g. Gandalfx64_q.iso.