RTM-ATCA-SXXX Overview
6806800H62B ATCA‐S201InstallationandUseGuide30
3.6.1 U-boot console tool
The ATCA-S201 employs a staged boot process that begins with U-boot. U-boot is
an open source boot loader program that is the first code executed at system reset.
As the boot execution commences, its progress may be monitored via the RS232
console port of the Advanced RTM. U-boot supplies several initialization
parameters to the Linux kernel that administrators may elect to modify. U-boot
employs a countdown timer with a default setting of bootdelay seconds, see table
below. If a key is pressed before this time, the auto boot procedure halts and the
administrator will see a U-Boot command prompt:
...
Hit any key to stop autoboot: 5
uboot=>
3.6.1.1 When is U-boot needed?
Users may never need the U-boot environment. U-boot is included to
accommodate atypical system maintenance situations such as:
On site field servicing (must be connected via serial console)
Network boot (rather than flash boot)
Environments without a DHCP server
Flash recovery
3.6.2 Essential U-boot user commands
The U-boot console environment includes a rich set of commands that can be listed
on the screen using the following command:
uboot=> help
Typically, only a handful of commands are needed to configure a new ATCA-S201.
The essential commands are covered in the table below.
Table 8 Essential U-boot configuration commands
U-boot command syntax description
printenv
Displays a list of all U-boot environment variables and
their current values. See section 3.6.3 for details.
setenv <variable_name>
<new_value>
Used to create or modify a U-boot environment variable.
New variables will be automatically created, existing ones
overwritten. When called without a <new value>, it will
delete the matching <variable_name> from the U-boot
environment if it exists.
saveenv
Used to saves environment variables to flash device,
which is loaded upon subsequent system power cycle or
reboot.
Variable changes that are not saved exist in RAM only,
