This chapter explains about the boot modes and available functions of the bootloader.
6.1. Bootloader Boot Modes
When the bootloader starts up, it switches to one of two modes depending on the state of the slide switch of the USB serial converter. For details about the USB serial converter slide switch, refer to 「Slide Switch Configuration」.
表6.1 Bootloader Boot Modes
Boot Mode Type
The U-Boot command prompt starts from which various configuration is possible.
Auto boot mode
The Linux kernel is automatically booted after power on.
When a USB serial converter is not connected, auto boot mode is used and the Linux kernel boots.
By default, the console is set to the environment variable "console", the baudrate of the console is set to the environment variable "baudrate", and the root file system is set to the environment variable "mmcroot".
When wanting to add Linux kernel boot options, it is convenient to use the "optargs" environment variable.