Jasper: Thanks, I think I've got the dracut conf. I've done this: 

kbingham@charm:~/iob/lenovo-x13s/v6.9$ cat /etc/dracut.conf.d/99-x13s.conf 
# Include specific files and directories in the initramfs
install_items+=" /usr/lib/firmware/qcom/sc8280xp/* "

 (still working through things though as still don't have all the remoteprocs running yet)