Upgrade instructions (important)

Please read this chapter carefully before upgrading the EMMC!!!

Download address of the upgrade tool (download the corresponding
version according to the following table)  upgrade_tool  Android_tool

Firmware  <font color=#ff0000>Official firmware </font>: The Ubuntu
firmware files with MBR are deprecated which are compiled from the old
and not-maintain-anymore SDK. Please use the ones with GPT compiled
from the new and polished SDK.  <font color=#ff0000>DIY firmware
</font>: The firmware compiled according to compiling Ubuntu firmware
(GPT) is GPT firmware.

Please read the following table carefully before upgrading :