Adding Adaptive/Smart Cruise Control to SEL model

I have been wanting to do this for a long time. I have a radar with front harness ready to install. Looking at some wiring diagrams I also concluded the SCC button is probably just painted and ECU coded differently...

I found this about adding a radar:
https://rts.i-car.com/collision-repair-news/calibration-research-tips-hyundai-variant-coding.html
"...adding radar sensor ... will set a variant coding DTC..."

The Kona has a Mobis instrument cluster according to:
https://en.yna.co.kr/view/AEN20180509004100320
http://www.koreaherald.com/view.php?ud=20180509000732

Which is not clearly supported:
https://canhacker.com/product/ch-obd-m02-can-coder/
https://canhacker.com/can-coder-new/
I sent an email to them asking,
"Is the Kona Electric with Mobis instrument cluster supported for recoding SCC ?"
No answer yet, but I will assume not.

Related to all this, I installed openpilot and some forks supported steering only which works way better than stock LKAS on long trips, but trying to update to much improved versions has been a huge PITA and frustrating.

So back to SCC, I plan to cut the new harness to wire the radar directly to the CAN bus via the openpilot Y harness so the stock harness is untouched in case of warranty concerns. A lot of openpilot people have been doing all kinds of CAN bus mods so that gives me some extra confidence to find a solution.

If I can isolate the radar CAN to only talk to the openpilot hardware then the DTC will be avoided. The radar will probably need to be activated from either extra code in openpilot (like the Tinkla project) or a repurposed White Panda I have, connected in between.

https://github.com/commaai/neo/blob/master/car_harness/open_pinout.sch.pdf

 

https://tinkla.us/images/thumb/6/63/Tesla_OP_Diagram.png/800px-Tesla_OP_Diagram.png
This Tinkla Radar to White Panda diagram example is a good place to start.