Hi, LibreELEC 12.0 on Orange PI PC does not work CEC for remote control, LibreELEC 11.0 image behaved similarly. A similar problem is solved here Allwinner H3: Orange Pi PC CEC degraded for SONY TV in 11.0 and 12.0-devel from working perfectly in 10.X -devel-from-w/. The only way to a working CEC is to fix 0071-HACK-SW-CEC-implementation-for-H3.patch.
Replace *pc-plus with *pc, recompiled, restarted, fixed the problem
0071-HACK-SW-CEC-implementation-for-H3.patch:
of_machine_is_compatible("xunlong,orangepi-pc-plus", override *pc-plus with *pc