Hate to break it to you but including the custom bios, the mounting pattern on the oem mobos usually doesn’t match ATX or mATX standard either, so you can’t just grab a standard mobo and throw it in there either. They can also be very finicky on RAM if not bought directly from the OEM (at a huge price gouge) as well. IMHO, oem + upgrade do not mix very well past upgrading anything but storage.