I am not responsible for bricked devices, dead SD cards, thermonuclear war, or you getting fired because the alarm app failed. Please do some research if you have any concerns about features included in this ROM before flashing it! YOU are choosing to make these modifications, and if you point the finger at me for messing up your device, I will laugh at you. A lot.
For several years I have been frustrated with CM and LOS being unable to connect to my car. To compound this, most custom ROMs are based on these ROMs and use the same BT stack making it nearly impossible to find a custom ROM that works with my vehicle. I had assumed that it was hardware driver related until I found that it happened with the Oneplus 3T as well. I was beginning to lose hope.
But thankfully, it turns out that AOSPA uses a different BT stack that actually works with my car, so I spent several weeks researching ROM building and was finally able to build my favorite ROMs with AOSPA's BT stack! I have made a flashable zip using a bluetooth file found in the stock ROM to fix the issues I've been having. The zip is below. If you have a different device and would like this fix feel free to pm me to make a zip or just follow the instructions in post 2 for how to apply the fix in TWRP without a zip.
-I only have a Oneplus 3T, not a 3. This zip should work on both, but keep this in mind.
-This will only fix the issues you're having if the ROM you're taking the file from has Bluetooth that works.
BT Fix v1.2
[LOS][RR][GZR] Bluetooth Fix for Existing ROMs, ROM for the OnePlus 3
shadeau, TheCrazyLex, Thecrazyskull, arter97, xboxfanj, chrislahaye, carlosavignano, arzbhatia, scoobyjenkins, martinusbe, otisman, akhilnarang, varund7726, westcrip
ROM OS Version: 7.x Nougat
ROM Kernel: Linux 3.x
ROM Firmware Required: OOS 4.1.6 or later
Based On: AOSP, LineageOS
Current Stable Version: 1.2
Stable Release Date: 2017-09-20
Last Updated 2017-11-21