There's a pdf instruction on the Hyundai accessories page for installing the Homelink mirror. It gives pretty clear instructions on how to remove the pillar trim.
Homelink Mirror Installation
Note: The mirror kit comes with replacement tether-clips and asks you to cut the old ones with side cutters. You may need to get creative to remove this without breaking it. If they're anything like the ones on my old Mazda 6, they're a pain in the ass to reach, but if you can get in there and squeeze both sides, you should be able to unclip where it snaps into the pillar.
Also Note: This instruction also shows how to access power for hard-wiring.

 

EXCELLENT!! thank you. looks very close to the elantra. i checked the headliner, and it appears there is a small space in the front of the headliner to easily tuck the wires in. also, on both of our e's, i was able to just pop out the trim, and get the wire around the airbag, and down to the fusebox. too bad the camera system in these cars dont have recording

 

When I installed my homelink mirror, I didn't have to remove the covers. I was able to tuck the wiring into the headliner and A piller without removing anything.

 

I have found that the less you have to disassemble, the better. Definitely tuck.
Back in the day (before airbags and all this tech stuff), I used to do custom install work and fabrication, and though straight forward, it had it's challenges. Now days, so many sensors, airbags, and automotive voodoo, gotta be super careful. Nice to have the internet to be able to research how to do it or, like here, see if anyone has already done it (and where to order the part you messed up removing it, LOL )
9to5toys.com, before the Coronapocalypse, found great deals on great stuff, including dash cams. Mine cam into play when a garbage truck crossed the center line and almost gave me a bad day. I retrieved the footage, clearly showing truck number, time, day, GPS location and even the drivers cell phone in his hand and a surprised look on his face, and sent it to the Garbage Company. They replied, apologized and disciplined the driver. Get the HD, worth it.

 

we used to have 2 2016 elantras(traded one in on the sonata), and i installed 2 pioneer radios, and front and rear dashcams in both. most of the trim removed for these installs are not held in by much, they just snap in/out, and have a couple of screws to make sure they stay in place. the homelink mirror install looks exactly like the elantra homelink, the exact same pieces come out, even the clips and screws are in the same place. i am getting the hardwire kit that allows the parking function. iow, when the car is parked and off, the cameras still record, and they have motion sensors. so if someone dings the car, ima going after them.

 

I'm curious what you guys are using dashcams for primarily? Documenting nonsense?

 

Yes the trim clips are almost designed to break it seems. I just traded in an Infinity that the B pillar clips disintegrated upon removal and you had to order the whole cover. In the old days they were metal, now its probably recycled cheap plastic, LOL. We just have to take our time and be careful.
And to answer your question weigojmi, its really nice to have documentation in case of an accident. I have used the footage in mine twice in a year. Once was the garbage truck incident, and then when someone hit my wife's car in a parking garage. Oh, and as a bonus, got some great audio of the wife singing.
That's gold right there.

 

Yes the trim clips are almost designed to break it seems.

They're actually REALLY strong. They're designed to allow the trim piece to come loose allowing the airbag to deploy, yet keep the trim tethered to the pillar so it doesn't go flying around the cabin.

The tiny clips meant for most non-removable panels on the other hand...yeah, they're junk. lol