I uploaded the test image LibreELEC-S812.TEST_DTB.arm-8.0.2.img.gz and a set of test dtb files for separate use. This version of the image allows to use a separate c file dtb data. To use. After writing the image to media you can try running the system WITHOUT the dtb file. The script will try to dtb data from the internal memory and try to run them the system. If within 5 minutes of not going on the appearance of images on the screen, you need to add to the media one of the matching files, and rename it in the "dtb.img". You can try all the dtb files from the site, trying to get a working system.
Pay attention, this image is NOT INTENDED to be installed in the inside memory. If you try to run setup - you will receive a brick that need to be recovered.
In the near future I plan to upload additional versions of SYSTEM files with different content and settings WiFi network and BT. These files SYSTEM can be combined with different dtb files, is to try to pick up a working system (WiFi and BT).
Link to the test directory.
Yandex.Disk
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I tried both ways on my m8s and get same thing.
Note that multi download version works on Android >5 on version 4.4 is not working.
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When I remove SD card system boots normally form box RAM with old Kerber's Libreelec 7.0.2.001 (Kodi 16.1) which work perfect.
Show the output of fw_printenv after completed the multi-boot activation.