I found Mark Yoder's instructions for updating the BeagleBone's kernel to the preempt_rt kernel at
Thanks Mark.
I performed the same steps on my BeagleBoard X15 board except I used the command:
sudo ./update_kernel.sh --ti-rt-kernel instead of sudo ./update_kernel.sh --bone-rt-kernel
Was that correct for the BBX15? It ran and seems to have updated the kernel to the rt kernel according to uname -a. I saw a few warnings as the install printed messages to the console so I want to make sure I performed this correctly.
Thanks