UEnv.txt

This is a bootscript, the file that defines the boot configuration, similar to the bootloader. Unlike the U-boot, uEnv.txt is an editable text file. Some of the parameters are described in the kernel-parameters.txt

Sample settings

located in "/dev/nanda" (need to be mounted), uEnv.txt can be as follows:

console=tty0
extraargs=console=ttyS0,115200 hdmi.audio=EDID:0 disp.screen0_output_mode=EDID:1280x720p50 rootwait panic=10 rootfstype=ext4 rootflags=discard
nand_root=/dev/sda

and from another page

autoload=no
ethaddr=12:34:56:78:99:aa
fdt_high=ffffffff
serverip=192.168.1.130
bootargs=earlyprintk console=ttyS0,115200
boot_tftp=dhcp; tftp 0x46000000 arch/arm/boot/uImage; tftp 0x49000000 arch/arm/boot/dts/sun7i-a20-cubieboard2.dtb; bootm 0x46000000 - 0x49000000 
uenvcmd=run boot_tftp

And another

fexfile=script.bin
kernel=uImage
extraargs=root=/dev/mmcblk0p7 loglevel=8 rootwait console=ttyS0,115200 rw init=/init mac_addr=00:AE:99:A3:E4:AF
boot_mmc=fatload mmc 0 0x43000000 ${fexfile}; fatload mmc 0 0x48000000 ${kernel}; bootm 0x48000000

Commonly used parameter Definitions

Kernel specific

console=tty<n>

usage console=device,options where device and console are described in serial-console.txt.

root= /dev/XXXX *

root file to boot location. change XXXX to desired partition. interchangebale with "nand_root="

rootwait

Wait (indefinitely) for root device to show up. (e.g. USB and MMC devices)*

ARM / Allwinner specifics

nand_root= /dev/XXXX

root file to boot location. change XXXX to desired partition

rootfstype=ext4

rootfs partition type. usually ext4, but need to be change to the coresponding partition type.

To Be Completed....

WIP, that's why it is still a mess