Specifications

- print values of all environment variables
printenv name ...
- print value of environment variable 'name'
tftpboot - boot image via network using TFTP protocol
Usage:
tftpboot [loadAddress] [[hostIPaddr:]bootfilename]
=>
5.8. The First Power-On
Note: If you bought your m28 board with U-Boot already installed, you can skip this section since the
manufacturer probably has already performed these steps.
Connect the port labeled ttyAMA0 on your m28 board to the designated serial port of your host, start the
terminal program, and connect the power supply of your m28 board. You should see messages like this:
=>
=> reset
resetting ...
U-Boot 2012.07-00471-ge8925d7-dirty (Oct 01 2012 - 18:20:02)
CPU: Freescale i.MX28 rev1.2 at 454 MHz
BOOT: SSP SD/MMC #0, 3V3
I2C: ready
DRAM: 256 MiB
NAND: 256 MiB
MMC: MXS MMC: 0
In: serial
Out: serial
Err: serial
Net: FEC0 [PRIME], FEC1
Hit any key to stop autoboot: 0
=>
You can interrupt the "Count-Down" by pressing any key. If you don't you will probably see some (harmless)
error messages because the system has not been initialized yet.
In some cases you may see a message
*** Warning - bad CRC, using default environment
This is harmless and will go away as soon as you have initialized and saved the environment variables.
At first you have to enter the serial number and the ethernet address of your board. Pay special attention here
since these parameters are write protected and cannot be changed once saved (usually this is done by the
manufacturer of the board). To enter the data you have to use the U-Boot command setenv, followed by the
variable name and the data, all separated by white space (blank and/or TAB characters). Use the variable
name serial# for the board ID and/or serial number, and ethaddr for the ethernet address, for instance:
=> setenv serial# DUTS
=> setenv ethaddr !!!!!!FILL_THIS!!!!!!
Can't overwrite "ethaddr"
=>
Use the printenv command to verify that you have entered the correct values:
5.8. The First Power-On 41