第8章 Boot Modes and Bootloader Functions
This chapter explains about the boot modes on the Armadillo-400 Series and also about the boot configuration functions of Hermit-At, the default bootloader.
JP1 can be used to select between the on-board flash memory boot mode and the UART boot mode on the Armadillo-400 Series. In the on-board flash memory boot mode, the bootloader stored in the bootloader region of flash memory is booted. The UART boot mode is used for system restore when, for example, the bootloader stored in flash memory has been damaged. For more information, refer to "Restoring Bootloader to Factory State" in the "Armadillo-400 Series Software Manual."
In on-board flash memory boot mode, the bootloader stored in the bootloader region of flash memory is executed at power on.
With the default bootloader (Hermit-At), JP2 is used to select between auto boot mode, where the kernel is automatically booted, and maintenance mode, where it is possible to carry out various configuration.
Each boot mode is detailed in 表8.1「Boot Modes」.
表8.1 Boot Modes
| Mode | JP2 | Description |
|---|
| Auto-boot | Open | The Linux kernel is automatically booted after power on. |
| Maintenance | Short | The Hermit-At command prompt that can be used for changing configuration is started. |
8.2. Linux Kernel Boot Option Configuration
Various settings including console and root filesystem settings can be changed by specifying the appropriate Linux kernel boot options. The following details some options typically used with Armadillo.
The setenv function of Hermit-At is used for this configuration. Parameters set with setenv are saved to flash memory and remain in effect even after rebooting.
The clearenv command is used to clear any set parameters.
8.2.1. Console Configuration
To change the output console of the boot log, set the console parameter as shown below.
For the effects on logging for each setting, refer to 表8.2「Console Configuration Effect On Output Destination」.
表8.2 Console Configuration Effect On Output Destination
| Console Option | Boot Log Output Destination | Maintenance Mode Prompt Destination[] |
|---|
| ttymxc1 | CON3 (Serial Interface 1) | CON3 (Serial Interface 1) |
| ttymxc2 | CON9 (Serial Interface 2) | CON9 (Serial Interface 2) |
| ttymxc4 | CON9 (Serial Interface 3) | CON9 (Serial Interface 3) |
| null | None | CON3 (Serial Interface 1) |
| Other (tty1 etc) | The specified console[] | CON3 (Serial Interface 1) |
![[警告]](images/warning.png) | |
|---|
If the kernel console is set with setenv, this configuration is also carried over to the Hermit-At console. For example, if the kernel console is set to ttymxc2, the Hermit-At console will also change to ttymxc2 from the next boot. |
8.2.2. Specifying Image File To Boot
On the Armadillo-400 Series, in addition to on-board flash memory it is also possible to boot an image file from storage or a tftp server. For more information, refer to "Kernel and Userland Placement" in the "Armadillo-400 Series Software Manual."
8.2.3. Other Boot Options
There are a large number of options available aside from those introduced here. For more information refer to a book on the Linux kernel or the documentation included in the Linux kernel source code (kernel-source/Documentation/kernel-parameters.txt).
8.2.4. Boot Option Configuration Examples
