At the simplest, enter the bios and choose to boot from usb or hard drive, depending which you want to use.
Thanks, I did attempt that. Even when I disabled the hdd from the boot options, it would boot off the USB (show the LibreELEC Kodi splash) and then proceed to load PMP off the hdd. I'll dig a bit deeper into the bios to see if there's anything I missed.
I really hoped going from PMP to Kodi would be as easy as popping the Kodi LibreELEC USB stick in and telling PMP to reboot.
[hr]
I think you should manually set different volume labels at least on USB stick or use UUID in extlinux.cfg.
Interesting. Thanks, I'll take a look at that!
Edit: upon further searching based on the "extlinux" tip, I came across this thread which I believe would be applicable to my situation: LibreELEC I'll follow-up confirming if it works for me too.
Edit 2: Confirmed that this fixed things for me. On my hdd extlinux (this is PlexMediaPlayer /flash/extlinux.conf) I changed it to:
APPEND boot=/dev/sda1 disk=/dev/sda2 ssh quiet
and then on the USB stick (this is Kodi mounted while PMP is running: /var/media/System/extlinux.conf):
APPEND boot=/dev/sdc1 disk=/dev/sdc2 quiet ssh
This has allowed me to run Plex as my everyday system (hdd) and when I want to use Kodi, I plug in the USB stick and select reboot from the Plex menu. Similarly, if I am using Kodi and want to go back to Plex, I select reboot from the Kodi menu and pull the USB stick. Plex then boots up. Just what I wanted. Thanks again for the pointers!