I think you're mixing apples and oranges here. There are different files out there that have Xtreme in the title but not all of them are full-blown images of a DTivo OS. The 2.5Xtreme images are complete images of a DTivo OS at version 2.5. The 2.5.2Xtreme files are also full images of a DTivo at version 2.5.2. This is where the confusion lies because Superzap's 2.5.2 xupgrade program only contains the delta info between 2.5Xtreme and the 2.5.2 OS as well as the xPlusz utility containing all of the popular hacks.
The best course of action for getting your DTivo to version 2.5.2 is to install 2.5Xtreme and then install SZ's 2.5.2 upgrade. The 2.5.2Xtreme image is NOT the same as the 2.5Xtreme -> 2.5.2 upgrade. Attached is a tutorial I wrote up that will put you on the right track.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!