Datasheet

• bootargs: the kernel command line, bootloader passed to kernel. Described in 4.3.2 section, bootargs env is a
optional for boota. There is a default bootargs stored in boot.img. If the bootargs env isn't been manually set in uboot,
the default on in boot.img will be used. If you want to use default env in boot.img, you can use command below to
clear the bootargs env.
> setenv bootargs
• dhcp: get ip address by BOOTP protocol, and load the kernel image ($bootfile env) from TFTP server.
• boota: boota command will parse the boot.img 's header to get the zImage, and ramdisk, also will pass the bootargs
as needed (it will only pass bootargs in boot.img when it can't find "bootargs" var in your uboot env). To boot from
mmcX, you only need to do the following:
> boota mmcX
to read the boot partition (the partition store boot.img, in this case, mmcblk0p1), the X was the MMC bus number, which is
the Hardware MMC bus number.
> boota mmcX boot # boot is default
> boota mmcX recovery # boot from the recovery partition
If you have read the boot.img into memory, you can use this command to boot from
> boota 0xXXXXXXXX
● bootm: (only work in NFS case) start to run the kernel, for other case, we use boota command. ● splashimage: the virtual
or physical address of bmp file in memory. If MMU is enabled in board configure file, the address is virtual, otherwise, it’s
physical. See README in uboot code root tree for detail. ● splashpos: this option sets the splash image to a free position
‘x,y’ on the screen. x and y should be positive number, which is used as number of pixel from left/top. Note that left and top
should not make the image exceed the screen size. You can specify ‘m,m’ for centering the image. Usually, for example,
‘10,20’, ‘20,m’, ‘m,m’ are all valid settings. See README in uboot code root tree for detail. ● lvds_num: choose which lvds
interface 0 or 1 to show splash image. Note that we only support boot splash on LVDS panel, but not support HDMI or other
display device.
6.2.2
Kernel command line (bootargs)
Depending on the different booting/usage scenarios, you may need different kernel boot parameters set for bootargs.
Kernel Parameter
Description Typical Value Used When
console where to output kernel log by
printk
console=ttymxc0
or
console=ttymxc2
QWKS use
console=ttymxc0
EVB use console=ttymxc2
init tell kernel where is the init file init=/init All case for Android. "init" in
Android is located in "/"
instead of in "/sbin"
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SCM i.MX 6 Series Android User's Guide
NXP Semiconductors
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