Hi all, putting this in the DIY since I don't think this hack is well known, but shoutout to the forum user
doru who figured a lot of this out beforehand.
If you have a garage door opener or valved exhaust that uses the newer Security+ 2.0 (Homelink 4.0) or later standard, your E9X Homelink mirror doesn't work with it.
Rather than buy a repeater that downgrades to the less-secure 1.0 standard (and may not work with valved exhausts or non-owned garages that you also wish to open), you can open up your mirror and swap out the UGDO module in it with a newer version. This guide assumes you already have a Homelink-enabled mirror installed in your E9X, and you're based in the USA/Canada (European garage doors use a different frequency altogether, from what I've heard).
Parts/Tools Required:
-F10 2012 5 Series Homelink mirror. You can generally find one of these on eBay or at a junkyard.
Important: the mirror must have the same mounting bracket as your original E9X mirror. Some later model F10's use a new mounting bracket style.....this is a newer model mirror that has internal connectors that are not backwards compatible to your mirror's UGDO module. The specific model I found had the part numbers 015891025891 printed on the back, however you cannot go off of this part number alone as it is also used on older model mirrors with the outdated UGDO module. You need to ensure it came off of a 2012 or newer car, as well. Other cars like the 2012+ BMW X1 may also work as a donor part, but I cannot verify this so purchase at your own risk.
-Plastic trim removal tools, you can find these on Amazon. You will easily scratch the plastic on the mirror if you use a flat head screwdriver.
-Patience
the mirrors are hard to get apart.
Directions:
-Remove your original mirror from the car (there are existing guides on how to do this, search for those instructions).
-Open your original mirror by prying at the trim point about 1/4" back from the mirror. You'll see the groove where the trim meets the body of the mirror. Keep wedging your pry tools in the groove until you're able to stick the pry tool inside of the groove and into the body of the mirror. CAREFULLY slide your pry tool around the sides of the groove to loosen the plastic clips holding the trim to the body. Once you do this, the trim piece will come off, and this is the only thing holding the mirror itself to the plastic body.
-Remove the existing UGDO module from your existing mirror. You'll see it sitting behind the mirror and connected to the garage door buttons. It's held in by 2 plastic tabs, which can be loosened by hand. Also be sure to carefully remove the power connector cable from the UGDO module.
-Repeat the same removal steps listed above, but on the new mirror you've acquired.
-Swap the module from the new mirror into the old mirror. Everything should fit the same, including the power connector.
-Put the trim back on and remount your original mirror with the updated UGDO module installed.
-Follow the Homelink instructions to pair your remotes to it, and it should work now!
Hope this helps anyone looking for a more elegant and factory solution to making newer Homelink garage doors or valved exhaust systems work with their E9X!