I found the solution to use an old android box with amlogic 8726 to instal Libeelect fot KODI use.
I download the USB-SD creator app for mac. I showed generic AMD/INTEL and LibreELEC-Generic.x86_64-9.2.6.img
I inserted an SDcard and
I download the file LibreELEC-Generic.x86_64-9.2.6.img
then i write this image on the sdcard with the app.
I can see in the sdcard on the mac :
OK i veryfied with utility disk on my mac and saw the sdcard with
Volume physique externe USB • MS-DOS (FAT16) /Volumes/LIBREELEC 1/ disk3s1
capacity 536,9 Mo used 261,4 Mo
I put the sdcard in the sd port of the box
I reset and start boton so i had on the screen the A2 logo then recovery window. Nothing more. If i select update with EXT there is nothing in the sdcard to start an update.
Something wrong but i don't know why. If anybody can help me to ressucite this box to a simple media player, it would be aweful.