Ian Pat

Only one option - to close the contacts on the chip's internal memory, is to lock the bootloader on it and to give the opportunity to start either from SD card or via USB cable program the flasher.
Have you tried connecting the SD card with the loader on it, the output in the console changes ? You brought the full output of that goes to the console UART now ?

1. To obtain the desired numbers of contacts for circuit, need to see documentation for a specific model memory, or to search the Internet experience of other users on this model of TV Boxing.
2. The themes of s905\s912\s805\s812 is the description of how to use Linux. Or are you interested in how to collect the right version of the image with Linux ?

How to build your own version of Linux, you can read these links.
 
http://docs.khadas.com/
 
http://www.linux-meson.com/doku.php
 
http://openlinux.amlogic.com/