U-boot cmdline: Difference between revisions

From embeddedTS Manuals
(Cleaned up formatting)
(Clarified)
 
Line 1: Line 1:
The Linux kernel cmdline can be customized by modifying the cmdline_append variable.  If new arguments are added, the existing value should also be included with the new arguments.
The Linux kernel cmdline can be customized by modifying the cmdline_append variable.  The variable contents are clobbered when set, so be sure to specify the full desired cmdline string.
<source lang=bash>
<source lang=bash>
env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet
env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet
Line 5: Line 5:
</source>
</source>


The kernel command line can also be modified from from the onboard Linux.  From the linux shell prompt run the following commands to install the necessary tools and create the script:
The kernel command line can also be modified from from the on-board Linux.  Debian (and other distributions) provide a U-Boot utilities package that contains the tools necessary to create a U-Boot script:
<source lang=bash>
<source lang=bash>
apt-get update && apt-get install u-boot-tools -y
apt-get update && apt-get install u-boot-tools -y

Latest revision as of 14:01, 27 September 2018

The Linux kernel cmdline can be customized by modifying the cmdline_append variable. The variable contents are clobbered when set, so be sure to specify the full desired cmdline string.

env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet
env save

The kernel command line can also be modified from from the on-board Linux. Debian (and other distributions) provide a U-Boot utilities package that contains the tools necessary to create a U-Boot script:

apt-get update && apt-get install u-boot-tools -y
echo "env set cmdline_append console=ttymxc0,115200 init=/sbin/init quiet" > /boot/boot.scr
mkimage -A arm -T script -C none -n 'tsimx6 boot script' -d /boot/boot.scr /boot/boot.ub

The boot.scr includes the plain text commands to be run in U-Boot on startup. The mkimage tool adds a checksum and header to this file which can be loaded by U-Boot. The .ub file should not be edited directly.