Raspberry Pi 4B No Serial without `dtoverlay=disable-bt`

New to seL4
1

Hello! I was following the recently updated documentation to setup seL4 on the Raspberry Pi 4B.

My current issue is that there is no serial when dtoverlay=disable-bt is removed, the Pi simply hangs after the GPU test. If I place the line back into the config.txt file, U-Boot loads as expected, lets me fatload the file and jump into the kernel… At that point, the serial no longer functions, and the Pi seems to be doing something but sends nothing back.

Looking at the commit history, I noticed there was a way to patch the kernel in relation to this commit and the relevant commit messages, so I will attempt that, but any other comments and information would be helpful. Thank you.

2

Going back to the older version of the documentation, I followed the instructions to patch the sel4 kernel to use the serial0 interface instead of the serial1 interface. When I ran this (still with the dtoverlay=disable-bt line) U-Boot was able to launch and I was able to get into the kernel and run sel4test which succeeded.

I’m considering making this a Github Issue, but unsure whether this should be a change to the sel4 kernel’s overlay-rpi4.dts file in conjunction with an update to the documentation, or simply just putting these instructions back into the documentation.