Pi 3+ B with LibreElec Leia,
Rotate LCD display for the the 7" (element14.com) Raspberry plastic-cased Pi LCD display:
I took the card out of the Pi and used my laptop text editor (Apple Pro) that I used to flash the SSD to modify /System/config.txt (not RTF!) and added:
display_rotate=2
near the top of the file. Worked great! Pointing was translated from my mouse to correctly as a bonus.
IF THIS DOES NOT WORK! Make sure using the "ls -l" command the owner, group, and RWEX permissions are identical before and after changing the config.txt file as they were before! The Libre expects the user and group names, and associated file permissions to be a particular user and permission to be read correctly and executed!
Prof. Bill 