This method is the best method I have found so far. Thanks wim. It does seem to work. It looks like all I need to do to swap between regular os boot and WinPE boot is change the active partition. This might be the perfect way to do it. Is there any ideas you may have for limitations of this method? It sonds like it would work with uefi or mbr? If I used a x86 WinPE could this work no matter what OSArch or UEFI/MBR?
Win8.1SE x64 is needed for booting UEFI and UEFI secure and it can also be used for booting BIOS computers with MBR.
The advantage of Win8.1SE x64 is that it also supports 32-bit apps since it has the SysWOW64 support, which is not available in Win10PE SE.
Win8.1SE x64 contains all the drivers for booting any computer and I consider Win8.1 SE x64 as the Universal solution that allows booting from USB and HDD or from Network by using PXE wimboot. My Win8.1SE x64 contains also WinNTSetup x64 and AOMEI Backupper and AOMEI Partition assistant.
The dropbox cloud server can be used in any place to download the w81x64A.wim Boot Image file and a 7-zip selfextracting file containing the Boot and EFI boot files as made by UEFI_MULTI.exe for booting w81x64A.wim. The 7-zip SFX file can be used then for easily making bootable FAT32 USB-sticks for booting any UEFI or BIOS computer. Booting from USB-Stick is easily selected from F8 Menu and many computers boot already auto first from USB-Stick so that F8 is not even needed. The advantage is that you don't need to make changes in BIOS/UEFI settings and don't need to change the active partition as you proposed.
Another approach is booting from Network by using PXE wimboot which must be activated in BIOS on the client computer and can then be selected in BIOS Boot menu.
On a LAN this is working excellent for me, but I don't know if this can be used via Internet.
Booting from Network by PXE wimboot of Win8.1SE x64 would be a very handy solution.