Fixing BCD entries for Windows Recovery Environment (WinRE)

Of course, we have bootrec /RebuildBCD, but it only creates bare-bones BCD entries to boot the operating system(s) it discovers.

I have since learned that you can recreate the necessary entries for WinRE using the command

reagentc /enable

provided the file %SystemRoot%\system32\Recovery\WinRE.WIM exists.

For reference, here is the manual method:

There is an excellent write-up by Mark Wharton in the Acronis forum where I got all of the following information.

Essentially, the BCD as displayed by bcdedit /enum all contains three essential sections: One Windows Boot Manager section, then a Windows Boot Loader section for each OS (including WinRE) and a Device Options referenced by the "Loader" section for WinRE that specifies the ramdisk.

Windows Boot Manager
--------------------
identifier              {bootmgr}
device                  partition=\Device\HarddiskVolume1
path                    \bootmgr
description             Windows Boot Manager
locale                  en-US
inherit                 {globalsettings}
default                 {current}
resumeobject            {95712d80-09fe-11e4-82d5-80dbd73f896e}
displayorder            {current}
toolsdisplayorder       {memdiag}
timeout                 30

Windows Boot Loader
-------------------
identifier              {current}
device                  partition=C:
path                    \Windows\system32\winload.exe
description             Windows 7
locale                  en-US
inherit                 {bootloadersettings}
recoverysequence        {95712d87-09fe-11e4-82d5-80dbd73f896e}
recoveryenabled         Yes
osdevice                partition=C:
systemroot              \Windows
resumeobject            {95712d80-09fe-11e4-82d5-80dbd73f896e}
nx                      OptIn

Windows Boot Loader
-------------------
identifier              {95712d87-09fe-11e4-82d5-80dbd73f896e}
device                  ramdisk=[C:]\Recovery\14a69569-3069-11df-a60b-9fbdc7c34241\Winre.wim,{95712d88-09fe-11e4-82d5-80dbd73f896e}
path                    \windows\system32\winload.exe
description             Windows Recovery Environment
inherit                 {bootloadersettings}
osdevice                ramdisk=[C:]\Recovery\14a69569-3069-11df-a60b-9fbdc7c34241\Winre.wim,{95712d88-09fe-11e4-82d5-80dbd73f896e}
systemroot              \windows
nx                      OptIn
winpe                   Yes

Device options
--------------
identifier              {95712d88-09fe-11e4-82d5-80dbd73f896e}
ramdisksdidevice        partition=C:
ramdisksdipath          \Recovery\14a69569-3069-11df-a60b-9fbdc7c34241\boot.sdi

To get everything working, the recoverysequence key must contain the identifier of the WinRE "Loader" section. The latter, in turn, must reference a valid existing "Winre.wim" file and pass the identifier of the "Device options" section as a parameter.