CAUTION: If your box has a non-standard partition layout, you will see an error when trying to boot from internal memory for the first time. To solve it, you need to boot one more time from SD card and run installtointernal again.
Maybe you missed this or not ??
Hi, thanks for your reply. I did not know booting twice was necessary in this case too. However, I'm following kszaq's instructions above to share the android data partition with libreelec, not overwrite it. The link you posted says installtointernal would erase Android. I've done this on an S805 box, but I would like to keep the dual boot option on the S912 for the time being.