Including WinPE as pre-os for GSS2.5 has its advantages, but if you corrupt your WinPE somehow, that configuration becomes invalid for the creation of any boot image.
To restore to your configuration as when it was initially installed, meaning no subsequent edits are retained, for both 256 & 512 versions of WinPE, please follow the steps.
Ideally it's good to back up the default configuration before editing.