This page mainly introduces how-to user can customize linux kernel bootargs under Ubuntu.
You can edit file /boot/uEnv.txt to add the user bootargs.
The default file contents are similar as below:
$ cat /boot/uEnv.txt
#############################DO NOT TOUCH THIS OPTION#############################
rootdev=root=UUID=a92f7f2f-0d4a-4607-a45a-4549cfe71036
partitiontype=partition_type=generic
#############################DO NOT TOUCH THIS OPTION#############################
## Setup console
consoles=console=ttyS0,921600 console=tty0
## Setup FAN mode
fan_mode=auto
## Add user args here, spilt with space.
## e.g. Add bootargs 'test1=111 test2=222'
## boot_user_args=test1=111 test2=222
boot_user_args=
You can append your bootargs to the configuration boot_user_args=.
e.g. Add bootargs cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory systemd.unified_cgroup_hierarchy=0, the variable boot_user_args= should be as below:
boot_user_args=cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory systemd.unified_cgroup_hierarchy=0
This configuration is suitable for only the 5.15 kernel.
You can change the linux UART pins for normal usage by modifying the configuration console=
| UART mode | Configuration |
|---|---|
| Configure the UART for linux debug | consoles=console=ttyS0,<baud rate> console=tty0 |
| Configure the UART for general usage | consoles=console=tty0 |
eg. Enable linux UART console with 921600 baud rate should be as below:
consoles=console=ttyS0,921600 console=tty0
| Model | Baudrate |
|---|---|
| VIM3/VIM3L | 115200 |
| VIM4/VIM1S | 921600 |
Please make sure the bootargs are split with space and don't add quotation marks.
Save the file and reboot to take effect.
After reboot system, we can check current linux kernel bootargs
$ cat /proc/cmdline