Core issue
The configuration register boot field determines whether the switch loads an operating system image, as well as where it obtains this system image.
Note: The factory default configuration register setting for systems and spares is 0x0102.
Resolution
To check the configuration register of the switch, issue the show bootvar command, as shown in this output:
4006-SUPIII#sh bootvar
BOOT variable = bootflash:cat4000-i5k91s-mz.122-20.EWA.bin,1
CONFIG_FILE variable does not exist
BOOTLDR variable =
Configuration register is 0x2102
To change the actual configuration register, refer to this output:
4006-SUPIII(config)#config-register ?
<0x0-0xFFFF> Config register number
4006-SUPIII(config)#config-register 0x0102
To change the bootvar and boot from ldr use, refer to this output:
4006-SUPIII(config)#boot bootldr ?
bootflash: URL of the Boot helper image
slot0: URL of the Boot helper image
For more information, refer to Modifying the Boot Field and Using the boot Command section of Configuring the Switch for the First Time.
