I've created a wim with MDT and when I mount the .wim file to check it out, every single file is the way i want/need it.  However when I add a DP for the boot image, the .wim that's getting pushed gets modified and the winpeshl.ini file on this new .wim isn't the one on the old .wim.   Where is it getting this new file from?  

It's injected automatically during the boot image update process. TO my knowledge, there is no supported way to circumvent this.

What are you modifying in the ini?

OK,

I am assuming that you are importing your custom boot image into SCCM?

If so, you can then configure SCCM to inject a custom winpeshl.ini into the custom boot image.  I had to do this for when I integrated scripts and files etc to get out boot image to work with 802.1x authentication.

You need to locate and edit the OSDInhection.xml file and tell it to inject the custom winpeshl.ini file and not the default one.

:)

I just tried using the osdinjection.xml file to import my custom winpeshl.ini file and this doesnt seem to work, like it still gets over written.  I tested the method on a sample file so I know its copying files over.  How did you get yours to overwrite the default?  I am using sccm 2012 r2 deploying windows 7 and like you am trying to get 802.1x to work.