Adding Drivers to the built-in Windows Recovery Environment

Windows 7 and Windows 2008 R2 feature an out-of-box installation of the very useful Windows Recovery Environment (WinRE).  WinRE can save your buttocks… but what if your system is using storage drivers that are not available in the out-of-box WinRE environment?  Such as the VMware Paravirtual SCSI driver (PVSCSI)?

Fortunately, WinRE is just a modified WinPE image, so you can add drivers using DISM.exe, right?  Sure… if you can find the WinPE image that is used by WinRE!  Fortunately, there is a tool for this.

Open a command prompt on your Server 2008 R2 system, and run “REAgentC.exe /info”… the output will tell you where to find the image:

Recovery Environment: \?GLOBALROOTdeviceharddisk0partition2Recoverybb338b68-0d2c-11df-be64-84e1223bd0bb
BCD Id: bb338b68-0d2c-11df-be64-84e1223bd0bb

So, on the second partition of the first disk (also known as the “C:” drive, according to “Diskpart”), you will find a hidden “recovery” directory, with subdirectory “bb338b68-0d2c-11df-be64-84e1223bd0bb”.  Within here is “winre.wim”.

Now there is simply the matter of injecting the drivers. First, place all the drivers you wish to inject into an easily accessible directory (such as c:localtemp, in our example), and then run the following commands:

mkdir c:wimtemp
dism /mount-wim /WimFile:c:recoverybb338b68-0d2c-11df-be64-84e1223bd0bbwinre.wim /index:1 /mountdir:c:wimtemp
dism /image:c:wimtemp /add-driver /driver:C:localtemp /recurse
dism /unmount-wim /mountdir:c:wimtemp /commit
rmdir /q c:wimtemp

Et voila! We press “f8” on next reboot, select the recovery environment, and suddenly we have full access to the local disk.

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