How to Edit the registry on WinPE
1. Build Genric x86 ISO using MDT
2. from the deployment share copy \boot\Genric_x86.ISO
3. exapand the ISO and get \Sources\boot.wim
4. Mount WIM with the following command:
“Dism /Mount-Wim /WimFile:D:\winpe_x86\winpe.wim /index:1 /MountDir:D:\winpe_x86\mount”
6. Copy any files you want to include in the PE Disk.
7. Run regedit and select the HKEY_USERS hive.
9. Select File | Load Hive, then browse to the location of your Windows PE build. Select System mount\windows\system32\config.
10. Enter a temporary name for the hive like PE_Stuff.
13. Edit the registry to your pleasure.
14. Select File | Unload Hive... and confirm the Yes | No dialog, and ensure you dismount the registry every time, as having it locked will prevent a successful build of Windows PE.
15. Unmount image example:
dism /unmount-Wim /mountdir:D:\winpe_x86\mount /commit
16. Put the boot.wim in the ISO and test.