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NetBootLoader
NBL Operation
For example, in the event the first image specified is defect, the NetBootLoader will attempt to
load the next image specified. This is continued until either a valid image is loaded or no further
image is available.
If no valid image is found, the NetBootLoader remains available for inputs.
2.7.13
telnet Login
A telnet login to the NetBootLoader is only possible during the boot wait time or when the boot
operation has been terminated either by operator action or automatically by the NetBootLoader. In either case, the Ethernet port parameters and the telnet password must be set prior to
attempting the telnet login.
To effect a telnet login the operator performs the standard telnet login procedure. The NetBootLoader responds by requesting a login password. The operator then enters a password. If the
password is valid, the operator can now access the NetBootLoader. If the password is invalid,
the telnet login procedure is terminated and the boot operation continues.
In the case of an invalid password, the login procedure may be repeated as often as required
within the boot wait time or as long as the NetBootLoader telnet server is active after the boot
wait time has been exceeded. Once the NetBootLoader telnet server is terminated, a telnet login is no longer possible.
2.8
NBL Flash Operations
To achieve an operable system for an application, the application software may be programmed to NBL Flash memory. As mentioned before, the NetBootLoader supports the programming of up to four images to NBL Flash memory whereby each image is assigned its own
image number. In addition to this, it also supports the updating of the NetBootLoader itself as
well as data transfer from the NBL Flash memory to the data buffer and from the data buffer to
an FTP server. The following chapters provide information on performing the various types of
NBL Flash memory operations.
2.8.1
NBL Flash Offsets
The currently used NBL Flash memory is one uniform Flash memory. All offsets are based from
the beginning of this Flash memory area. The NetBootLoader itself is located at the beginning
of the NBL Flash memory area and for this reason this area cannot be used for other image
programming. To display an overview of the currently used NBL Flash memory organization
use the INFO command.
If the image is an operating system (which is the default case), it must be programmed without
an offset. When such an image is programmed to NBL Flash memory, the image length and
CRC information is also programmed along with the image. This information is used by the NetBootLoader to determine the validity of the image during the boot operation. During system
startup, a valid image is copied to DDR2-SDRAM address 0x0 and started at offset 0x0 (FDT
enabled) or 0x100 (FDT disabled).
If an offset is specified, the image will be programmed exactly at this offset without adding
length or CRC information. This option is intended for the storing of configuration information
which is required to be located in NBL Flash memory.
ID 1022-8317, Rev. 2.0
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