Options for modifying/repairing boot options in hidden system / efi partitions

Hi there, I have a story... the details of which aren't part of my question, but they are what led me to my question in some scenarios I could envision needing an answer. Here goes... some patience please:

I have a Lenovo T530 laptop which came loaded with Windows 7 Home Premium. I wanted to start working on doing an eval of Windows 10 Home edition as part of the free upgrade offer from MS.

I backed all of my data and Win7 install using file copies and disk image tools (not important which for now), and then cleaned all partitions from the drive. Please don't get concerned about the clean install vs required upgrade to get the Win7 license properly activated for Win10 issue :wink:.

I used some diskpart scripts to convert the disk to GPT, and install the partition layout I wanted prior to botting off the Win10 install USB. The partition layout was like so:

Partition 1: 100MB System/EFI NTFS Partition
Partition 2: 100GB Windows NTFS Partition
Partition 3: 2GB Recovery Tools NTFS Partition
Partition 4: 200GB Data NTFS Partition

Windows 10 installed and loaded fine, and booting the disk into a WinPE USB I was able to observe what I expected to see: that the 100MB System Partition held the BCD store, Windows was installed to the 100GB partition I created like I told it to, and the WinRE Recovery Environment files were installed to the 2GB Recovery Tools partition I created.


However, after capturing the Win10 image for later use (I'm not ready to give up space in my 200GB data partition to run Win7 and Win10 as dual boot...), I recovered the Win7 image taken before, over the the top of the newly install Win10 partition.

Result... failure to boot.

Before recovering the Win7 partition backup, I had used bcdedit from within the installed WinRE environment to add a Safe Mode with Command Prompt boot entry to the boot loader installed by Win10. This gave me the boot option screen on startup, where I was then able to choose that inconspicuous option in the bottom left corner in order to boot into WinRE AT BOOT TIME (I am NOT happy about most of the documented ways of getting into Win10 WinRE being pretty much only some trick of rebooting from within the installed OS), and attempted a variety of tricks using CLI's (bcdedit, bcdboot, and bootrec - which couldn't find ANY Windows installations).

I still just couldn't get Windows 7 to boot...

Then I noticed while in the boot options menu from the Win10 WinRE I was loading, that it had the top left option to Continue into the installed Windows 7 OS (so the WinRE boot menu detected that it was no longer the fresh Win10 install even though bcdboot couldn't find anything, interesting). I picked it and was delighted to see my restored Win7 OS load up. Trying a plain reboot resulted in the same boot failure, I had to first boot into the Win10 WinRE from USB, then choose the boot option to 'Continue' to load the installed Win7 OS.

Once back in the restored Win7 OS, I simply ran EasyBCD to rewrite the boot files, rebuild the BCD, and added a new single boot entry for the Win7 install to keep things simple. YAY, the laptop would now boot directly into Win7 without intervention.

QUESTION: outside of the specific scenario I encountered, is there any environment (WinPE, or Win2Go) that I could boot into from portable media (say a bootable USB) where I could run EasyBCD. A vanilla WinPE throws a bunch of dependency errors when trying to run EasyBCD.

In addition, in the case of a hidden system partition that is not visible to the running Windows OS, is there no way for EasyBCD to be able to access boot entires in such hidden partitions? For instance, with the new Windows 10 boot loader, I'd love to be able to manually configure a boot entry for the Win10 Recovery environment installed in the Recovery Tools partition... but on this install, I couldn't even assign that partition a drive letter to be able to access it.

Thoughts on these two questions are appreciated... so long as you know what you're talking about :smile:.
Ignore the GPT info... that was part of an earlier attempt. Since then I'd wiped the partitions again - switched BIOS back to hybrid UEFI + Legacy MBR mode from pure UEFI mode - and then created the partition layout I described in MBR format...


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Well, I've got a working Win7 laptop again - but I'm stuck for how to manipulate the boot menu on a system that follows Microsoft / Manufacturer default partitioning practices...

EasyBCD has no way of accessing the hidden 'Recovery' partition where I've copied all of WIM images to - because it can't be assigned a drive letter in regular running Windows. It gets a drive letter under any PE environment - which is how I'm able to copy my utility WIM images to the partition, but I have on way of using EasyBCD to use them to edit the boot menu.

Any suggestions here? If it helps - please ignore the whole story above - probably got in the way. But given this partition layout - how can anyone use EasyBCD?

Partition 1: 100MB System/EFI NTFS Partition (location of BCD store)
Partition 2: 100GB Windows NTFS Partition
Partition 3: 2GB Recovery Tools NTFS Partition (location of recovery tools, utility PE/WIM images, etc)
Partition 4: 200GB Data NTFS Partition