You are writing conflicting information, this is your own problem.
I can't help if you don't explain better what you want to do, which is why I asked for more info
From what you said before my post you want to use OpenWrt as the main firmware for that device. That is not a phone anymore but a battery powered wireless 4G modem with a large screen showing a console.
Which is imho nonsense, but I posted a link to developer documentation you can use for that.
If the goal as you said in the last post is a more generic ""trying to implement an external security layer on this the one most vulnerable and hacked platforms of our times"
For that, I think you just want to run OpenWrt as a "firewall application" inside an actual phone OS, not fully replace the firmware with OpenWrt.
For that, you should be looking into virtualizing OpenWrt inside the phone (OpenWrt can be virtualized in most known hypervisors and your phone can run KVM/QEMU https://openwrt.org/docs/guide-user/virtualization/qemu?s[]=kvm&s[]=guest and also run as a docker container, see here Running OpenWrt in a Docker container ) and redirecting all network traffic to the VM/container so it can act as router/firewall.
If you run it like that you can operate it from a browser inside the phone OS, and you don't need to port any driver since you are just passing through network interfaces.