Core issue
The switch reports the device does not contain a valid magic number error message and fails to load the Cisco IOS Software image. The issue is caused by a corrupted file system on the device from which the CPU tries to load the Cisco IOS Software image.
Also when you enter the dir disk0: or dir slot0: commands, an unformatted Flash PC card returns a bad device block info or invalid magic number error message. For details on Flash cards, refer to the Supervisor Engine Flash PC Cards section of Catalyst 6000 Family Flash Card Installation Note.
Resolution
In order to resolve the issue, perform these steps:
- Go to ROM Monitor (ROMmon) mode.
- Manually boot the image using bootflash.
- Check whether the size of the image in slot0 is the same as the image size downloaded from the TFTP server.
- If the image size is the same, format the slot0 or disk0 and download a new image from the TFTP server by issuing the copy command.
- Check whether the image has been downloaded directly from TFTP to slot 0 or downloaded to an ATA card and then copied from ATA cards to slot 0. If the image has been downloaded directly to the ATA cards, format the ATA cards before downloading the image from the TFTP server.
As an alternative, perform these steps:
- Download the software again, and copy it to the Flash card.
- Copy the software from the Flash card of another switch within the same series.
For additional information on how to format or erase files from Flash permanently, refer to article How to format or erase files from Flash and NVRAM permanently.
Error message
device does not contain a valid magic number
