Thank you MatteN, CvH and mglae ! It worked perfectly!
I installed Gparted Live on the USB thumbdrive. I pressed delete to get into the bios of the machine, and chose to boot from the USB thumbdrive. I used Gparted Live to increase the size of the partition to 512MB, then rebooted the machine from the main SSD drive. From within the LIBREELEC CONFIGURATION add-on I chose the 9.0 Update channel and updated to 9.2. I rebooted the machine and then did the same to update to 10.1.
It's all working perfectly. Thank you!