[J.L.C.]

ssh root@<ip address><enter password, default is 'libreelec'>
mount -o remount,rw /dev/sda1 /flash
nano /flash/syslinux.cfg<add ' pci=nomsi' after 'quiet'>
<save and quit: CTRL+O CTRL+X>
reboot

Thanks. I'm running an Asus Chromebox (Haswell) which was modded maybe four-five years ago. After running the mount command, nano still brings up an empty file. As an aside, I'm really interested in how all this will play out. A new stable release should be coming soon. 

I also don't have a syslinux.cfg file