Enabling Booting From Flash Memory - Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual

Implementing Other Configuration Tasks
In the preceding command display output, the character "e" means this special location has
been erased (which must be performed before any write operation). The character "b"
means that the data that is about to be written to this special location has been temporarily
copied. The character "E" signifies that the sector that was temporarily occupied by the data
has been erased. The character "S" signifies that the data was written to its permanent
location in Flash memory.
The squeeze command operation keeps a log of which of these functions has been
performed so upon sudden power failure, it can return to the correct place and continue with
the process. The character "Z" means this log was erased after the successful squeeze
command operation.
The configuration register setting 0x0101 tells the system to boot the default image (the first
image) from onboard Flash memory, but not reset the Break disable or check for a default
filename to be booted over the network. The configuration register setting 0x0102 tells the
system to boot from Flash memory if netboot fails, disable Break, and check for a default
netboot filename.
For more information on the copy tftp:filename [bootflash: | slot0: | slot1: ]:filename
command and other related commands, refer to the set of configuration fundamentals
configuration and reference publications.

Enabling Booting from Flash Memory

To enable booting from Flash memory, set configuration register bits 3, 2, 1, and 0 to a value
between 2 and 15 in conjunction with the boot system flash device:filename configuration
command, where device is bootflash:, slot0:, or slot1:, and filename is the name of the file
from which you want to boot the system. (For a detailed configuration register information,
refer to the section "Manually Booting the System," earlier in this chapter.)
To enter configuration mode while in the system software image and specify a Flash
filename from which to boot, enter the configure terminal command at the enable prompt
as follows:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# boot system flash device:filename
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