In this post, I will explain some things about armboot boot loader that I have understood. The boot loader on NCB3AST is based on the open source Armboot, but modified by Star technology (unfortunately they don’t share their modification). You need to connect to the serial port using 38400N1. I am using kermit to connect, but you can use cu or other programs. To enter the Armboot boot menu, you must hold and press USB EXIT button while powering it on. You will start seeing delay tim 0 until 9, and after that, the device will try to connect to mass production server (I don’t know what the protocol is, but if we can reverse engineer this, this can potentially be used for unbricking the device without opening the device).