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?
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.