Update: With the later releases of Win10 post 1703, the offline servicing section doesn’t seem to load the drivers. As a fix, add the following lines to your setupcomplete.cmd batch file to load the drivers at the end of the OSD process.
pnputil.exe /add-driver "C:\Drivers\*.inf" /subdirs /install
pnputil.exe /add-driver "C:\Drivers\*.inf" /subdirs /install
pnputil.exe /add-driver "C:\Drivers\*.inf" /subdirs /install
Running pnputil 2 times seems to be the sweet spot to capture all of the hardware devices, because some hardware is hidden behind other hardware drivers (such as USB3 and PCI hardware)
Update: if you want to use the pnputil.exe command with versions of windows before Win10 you will need to use this command instead, since the older versions of pnputil do not support the /subdir switch.
forfiles /p "C:\Drivers" /s /m *.inf /c “cmd /c pnputil -a @Path”
forfiles /p "C:\Drivers" /s /m *.inf /c “cmd /c pnputil -a @Path”
forfiles /p "C:\Drivers" /s /m *.inf /c “cmd /c pnputil -a @Path”