Many thanks for your reply, jernej.
Regarding the temperature, I see that after a few minutes in the home the temperature is about 70 degrees centigrade (on Armbian in idle is about 50 degrees). I disabled the RSS feeds but for now I have not tested well if the situation improves.
About wiringOP, on armbian (OPI-PC) I had used https://github.com/zhaolei/WiringOP and It worked well in the few tests done. Nevertheless, with https://transfer.sh/ILHOt/tools.wiringop-7.0.1.zip in your openelec fork I get the following output of the command "gpio readall":
OpenELEC:~ # gpio readall
+-----+-----+----------+------+---+-Orange Pi+---+---+------+---------+-----+--+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+----------+------+---+----++----+---+------+----------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| | | SDA.0 | | | 3 || 4 | | | 5V | | |
| | | SCL.0 | | | 5 || 6 | | | 0v | | |
| 6 | 6 | IO6 PA06 | ALT3 | 0 | 7 || 8 | | | TxD3 | | |
| | | 0v | | | 9 || 10 | | | RxD3 | | |
| | | RxD2 | | | 11 || 12 | 0 | ALT3 | IO1 PD14 | 1 | 110 |
| | | TxD2 | | | 13 || 14 | | | 0v | | |
| | | CTS2 | | | 15 || 16 | 0 | ALT3 | IO4 PC04 | 4 | 68 |
| | | 3.3v | | | 17 || 18 | 0 | ALT3 | IO5 PC07 | 5 | 71 |
| | | MOSI | | | 19 || 20 | | | 0v | | |
| | | MISO | | | 21 || 22 | | | RTS2 | | |
| | | SCLK | | | 23 || 24 | | | SPI-CE0 | | |
| | | 0v | | | 25 || 26 | | | CE1 | | |
| | | SDA.1 | | | 27 || 28 | | | SCL.1 | | |
| 7 | 7 | IO7 PA7 | ALT3 | 0 | 29 || 30 | | | 0v | | |
| 8 | 8 | IO8 PA8 | ALT3 | 0 | 31 || 32 | 0 | ALT3 | IO9 PG08 | 9 | 200 |
| 9 | 10 | IO10 PA9 | ALT3 | 0 | 33 || 34 | | | 0v | | |
| 10 | 12 | IO12PA10 | ALT3 | 0 | 35 || 36 | 0 | ALT3 | IO13PG09 | 13 | 201 |
| 20 | 14 | IO14PA20 | ALT3 | 0 | 37 || 38 | 0 | ALT3 | IO15PG06 | 15 | 198 |
| | | 0v | | | 39 || 40 | 0 | ALT3 | IO16PG07 | 16 | 199 |
+-----+-----+----------+------+---+----++----+---+------+----------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+----------+------+---+-Orange Pi+---+------+----------+-----+-----+
Note the written "Orange Pi" instead of "OrangePIPC" and also the gpio numbering is different from that on armbian with https://github.com/zhaolei/WiringOP. Indeed I copied the folder compiled on armbian inside /storage in OpenELEC and I get:
OpenELEC:~/WiringOP # LD_LIBRARY_PATH=/storage/WiringOP /storage/WiringOP/gpio/gpio readall
+-----+-----+----------+------+---+--OrangePiPC--+---+------+---------+-----+--+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+----------+------+---+----++----+---+------+----------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| 2 | 8 | SDA.0 | ALT5 | 0 | 3 || 4 | | | 5V | | |
| 3 | 9 | SCL.0 | ALT5 | 0 | 5 || 6 | | | 0v | | |
| 4 | 7 | GPIO.7 | ALT3 | 0 | 7 || 8 | 0 | ALT3 | TxD3 | 15 | 14 |
| | | 0v | | | 9 || 10 | 0 | ALT3 | RxD3 | 16 | 15 |
| 17 | 0 | RxD2 | ALT3 | 0 | 11 || 12 | 0 | ALT3 | GPIO.1 | 1 | 18 |
| 27 | 2 | TxD2 | ALT3 | 0 | 13 || 14 | | | 0v | | |
| 22 | 3 | CTS2 | ALT3 | 0 | 15 || 16 | 0 | ALT3 | GPIO.4 | 4 | 23 |
| | | 3.3v | | | 17 || 18 | 0 | ALT3 | GPIO.5 | 5 | 24 |
| 10 | 12 | MOSI | ALT4 | 0 | 19 || 20 | | | 0v | | |
| 9 | 13 | MISO | ALT4 | 0 | 21 || 22 | 0 | ALT3 | RTS2 | 6 | 25 |
| 11 | 14 | SCLK | ALT4 | 0 | 23 || 24 | 0 | ALT4 | CE0 | 10 | 8 |
| | | 0v | | | 25 || 26 | 0 | ALT3 | GPIO.11 | 11 | 7 |
| 0 | 30 | SDA.1 | ALT4 | 0 | 27 || 28 | 0 | ALT4 | SCL.1 | 31 | 1 |
| 5 | 21 | GPIO.21 | ALT3 | 0 | 29 || 30 | | | 0v | | |
| 6 | 22 | GPIO.22 | ALT3 | 0 | 31 || 32 | 0 | ALT3 | RTS1 | 26 | 12 |
| 13 | 23 | GPIO.23 | ALT3 | 0 | 33 || 34 | | | 0v | | |
| 19 | 24 | GPIO.24 | ALT3 | 0 | 35 || 36 | 0 | ALT3 | CTS1 | 27 | 16 |
| 26 | 25 | GPIO.25 | ALT3 | 0 | 37 || 38 | 0 | ALT3 | TxD1 | 28 | 20 |
| | | 0v | | | 39 || 40 | 0 | ALT3 | RxD1 | 29 | 21 |
+-----+-----+----------+------+---+----++----+---+------+----------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+----------+------+---+--OrangePIPC--+------+----------+-----+-----+
where I added "LD_LIBRARY_PATH=/storage/WiringOP" because I have copied there "WiringOP/wiringPi/libwiringPi.so.2.0" renamed in "WiringOP/libwiringPi.so" and "WiringOP/devLib/libwiringPiDev.so.2.0" renamed in "WiringOP/libwiringPiDev.so". Otherwise I get the error "libwiringPi.so" and "libwiringPiDev.so" not found.
In the moment I could not directly test the gpio command installed via openelec addons with, for example, a LED or a relay, but I tested the above libraries ("libwiringPi.so" and "libwiringPiDev.so") copied in ~/WiringOP from armbian that work perfect.
In fact, I copied the folder "rcswitch-pi" compiled on armbian ("https://github.com/r10r/rcswitch-pi") inside /storage of openelec like before, and then the following command works perfectly:
LD_LIBRARY_PATH=/storage/WiringOP /storage/rcswitch-pi/send XXXXX X 1
etc. (My electrical outlet turns on)
The same thing works with the "codesend" command from "https://github.com/timleland/rfoutlet.git" compiled again on Armbian 5.20.