Raspberry Pi 3 or Raspberry Pi 3+
Use LibreELEC USB-SD Creator to write libreelec-rpi2.arm-8.2.4.img.gz to SD card.
Use LibreELEC USB-SD Creator to write libreelec-rpi2.arm-8.2.4.img.gz to USB memory stick.
Add “program_usb_boot_mode=1” (without double quotes) to config.txt on SD card just once and boot your Pi to flip a bit in a write-once register to enable USB booting.
Modify cmdline.txt and change this line:
boot=/dev/mmcblk0p1 disk=/dev/mmcblk0p2 ssh quiet
boot=/dev/sda1 disk=/dev/sda2 ssh quiet
Now your LibreElec will boot from USB. This will prevent SD card corruption and improve library fanart loading speeds.
Note: The SD card is still required as part of the initial boot process.
When the automatic update to 8.2.5 has taken place and the tar file has been extracted onto the USB stick at boot time, you will get the following warning message when you next boot your Pi:
NEVER TOUCH boot= in extlinux.conf / cmdline.txt If you don't know what you are doing, your installation is now broken. Normal startup in 60s...
LibreElec will now revert to booting from the SD card and ignore cmdline.txt.
Files on the SD card are version 8.2.4 and files on the USB memory stick are 8.2.5. This breaks USB boot and the system reverts to SD boot.
Simply manually copy everything from the USB memory stick over the top of the SD card (except for cmdline.txt). There is no need for a Kodi backup restore.