Xunwei-i.MX6 development board manual update-non-device tree uboot-modify default environment variables

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Xunwei-i.MX6 development board manual update-non-device tree uboot-modify default environment variables [Copy link]

This document mainly introduces how to modify the default boot parameters of non-device tree uboot. After the iTOP-iMX6 development board is burned, the default is the system parameters and screen parameters of the 9.7-inch screen of the Android system, as shown in the figure below. Enter the following command to view the default boot parameters printenv

74.1 Important environment variables
The more important environment variables or frequently used environment variables are already in the red box in the above figure.
Mainly: bootsystem, lcdtype and bootargs. These parameters can be set in the uboot source code. The specific file is: "iTOP-iMX6_android4.4.2/bootable/bootloader/uboot-imx/lib_arm/board.c" file.
74.2 Default boot system settings The
default boot system parameters are: bootsystem. Open the "board.c" file. Search for the keyword "bootsystem" and find the following code:

By modifying the "p = android;" statement, you can modify the default boot system parameters.
If you want the default boot system to be Android, modify p = "android";
if you want the default boot system to be QT, minimal system, YOCTO, modify p = "qt";
if you want the default boot system to be ubuntu, modify p = "ubuntu";
In the following program, you can see that the "boot_system_flags" flag is used. Search for this flag and you can find the following content.

74.3 Default screen settings
The default screen parameter is: lcdtype. Open the "board.c" file. Search for the keyword "lcdtype". Find the following code.
By modifying the "p = "9.7";" statement, you can modify the default screen settings. In the program in the screenshot above, you can see that the "displayArgs" value of the corresponding screen is set
by the "sprintf();" function . If you want to set the default screen to 9.7 inches, set "p = "9.7";" If you want to set the default screen to 7.0 inches, set "p = "7.0";" If you want to set the default screen to 4.3 inches, set "p = "4.3";" If you want to set the default screen to 1024x600, set "p = "1024x600";" If you want to set the default screen to 5 inches, set "p = "5.0";" If you want to set the default screen to vga_1024768 inches, set "p = "vga_1024768";" If you want to set the default screen to 10.1 inches, set "p = "10.1";" If you want to set the default screen to hdmi, set "p = "hdmi";" 74.4 Default bootargs parameter settings Open the "board.c" file. Search for the keyword "bootargs". Find the following code. You can modify the "bootargs" parameter settings here. The detailed codes introduced above are as follows:

Jacktang

Today's document has no code or pictures.

freebsder

A uboot script should be placed under /boot so that it can be changed without touching the code.