I'm at my wit's end here, I've tried all I can think of. I have this Mecool M8S Pro, I've been trying to root it, flash twrp, and install armbian. There is no way to access bootloader, or maybe it's the same as recovery. When I put armbian on an sdcard and made an armbian_first_run.txt file, I first tried using the update app. I picked the aml_autoscript.zip, and confirmed the update, then a message pops up and says "shutting down", then nothing I've left this for a long time and the box never comes back on. Basically, the box won't turn on if there is an sdcard in the slot. I've looked at all the logs available from the recovery screen and after I try this it says something like this: "failed to mount /dev/block/mmcblk0 (device or resource busy)". Even if I hold the reset button, the box turn on if there is an sdcard in the slot.
I have also tried flashing twrp, it doesn't work if I have it on an sdcard and boot to recovery because the box won't turn on if there is an sdcard in the slot while powering up, and if I plug it in after I boot to recovery the box won't see it when searching for files in update from EXT. The update also didn't work when I had it on a USB and tried to update from EXT. The message I saw on the log after trying this said something regarding cryptfs driver not working. There was an earlier error in the log, but it seemed to make it past this error. I can't install TWRP at least the two versions I have tried.
I have yet to try to put SuperSU zip on the box using update, or an apk using app installer. Would that help?
The main reason I mentioned no bootloader in the title is because, when I broke down and tried to use adb over Ethernet, I would run adb reboot bootloader, the box just turns off, regardless of whether there is an sdcard in the slot. I had to use Ethernet to debug, because when I plug in USB to the box there is a CD image that appears on my PC and I can't use adb over USB. So, I got adb to work with tcpip, but adb reboot bootloader does nothing. I got to a bootloader looking screen with adb reboot recovery, it gives me options like 'Update from ADB', 'Update from EXT', 'Wipe data', 'Wipe cache', 'Mount /system', 'Reboot system', 'Reboot bootloader' (just turns the box off), and more. Once I have reached this screen, adb devices lists the device as offline and I can't run fastboot commands such as 'flash recovery' or 'oem unlock'.
I'm at my wit's end.