Comment by ryanburk

the tools needed to create WinPE - that shipped in the OEM preinstallation kits (OPK) - did do some work against the original files to make the magic happen. it was mainly around the special registry dB needed to get it to boot, not changing the files themselves. we also did a ton to try to slim it down, originally to get it to fit on a CDROM or RIS/PXE boot. well before USB sticks got larger than CDROMs.