So, I wanted to combine the system reserved (with boot files) partition with the recover (WindowsRE) partition. Somewhere in the process I lost the ability to set the recovery environment to WindowsRE on the recovery partition so I decided to start over from scratch.

My HP DV6 laptop has a "hybrid" bios. It supports EFI booting but will not boot from a GPT disk. I wanted to verify this so I booted into MiniTool Partition Wizard, deleted all the partitions on my HDD and initialized it to GPT. I booted into Windows 10 USB created with the latest ISO downloaded from Tech Bench. I selected custom install option and pointed setup to the unallocated space on the GPT HDD and expected to get the "Can't install Windows to a GPT disk" error. Instead setup went through normally. Hmmm.....

So I let it finish, and then looked at my HDD in disk management. To my surprise, I ended up with an MBR disk with only 2 partitions on it - a 500mb System Reserved partition and the rest a Windows 10 system partition. So Microsoft seems to have changed two things when installing to a blank HDD. Setup will at least reinitialize the disk as MBR when GPT can't be used (have no way of checking if the reverse is true). And now, at least on MBR disks, Microsoft has combined the System Reserved and Recovery partitions. I verified my 500mb System Reserved partition contained both the boot files and the WindowsRE environment.

So, then I shrunk the Windows 10 system partition by 4.5gb, added the 4.5gb to the System Reserved Partition, copied all the files from the Windows 10 setup ISO (except for boot folder) to the System Reserved partition and then used EasyBCD to add an entry to the boot menu for Windows Setup pointing to the boot.wim file in the sources folder. I also added the install.wim file to the recovery environment using reagentc /setosimage.

Then I copied a Macrium Reflect Free rescue.iso and a MiniTool Partition Wizard ISO to the System Reserved partition and added bootmenu entries for the ISOs using EasyBCD. So, my computer is now exactly the way I want it, thanks Microsoft! One System Reserved partition that contains the boot files, WindowsRE environment, install.wim for system Reset, and boot menu options to run Macrium Reflect Free, MiniTool Partition Wizard, or clean install Windows all from the System Reserved partition!