stroma

@Aurelio: Yes I used method described in the youtube video above.
 
You will need serial cable connection to the PCB and adb.
The 4 pin connector on the PCB is used for the serial connection. Cheap USB<->Serial converter can be used, note the voltage level of the signals is 3V3 (only GND, RX and TX pins are needed), serial speed is 115200 bps.
 
I can't say much about the performance compared to RPi. Since the armbian filesystem is on USB 2.0 flash the file operations are rather slow. I successfully installed OctoPrint with web camera support and it seems to fork fine.
 
I still not try to write the image to internal eMMC, I want to be able to backup the stock android and have a method to restore it if needed. For now I backed up the eMMC content with
dd if=/dev/mmcblk1 iflag=fullblock oflag=direct bs=512k | gzip > tvbox-backup.img.gz but I'm not sure if this file is useful.
 
Edit:
armbianmonitor result

@schultzz The information you need is in first post on this thread, Unbrick paragraph.