A Catalyst 2940, 2950, 2955, 2970, 3550, 3560, 3750 or 3750 Metro Switch can experience boot errors or can constantly reboot.
If the switch does not boot properly, it can be due to one of these reasons:
If the switch is unable to load a software image located in Flash, the system boots up with a switch: prompt.
If a message that indicates an error loading flash is displayed during the system bootup, it indicates that the software image present in the Flash is corrupt or missing.
If the switch continuously reloads, the boot sequence has to be broken. Press the Mode button on the Catalyst 2950, 2970, 3550, 3560, 3750 or 3750 Metro Switch in order to do this. Un the case of the Catalyst 2955, issue a break key sequence from the keyboard in order to do this.
Complete these steps in order to resolve this issue:
Issue the dir flash: command in order to check the image in Flash.
Verify that the image is present, the file size is correct and that this is the correct image for the platform.
If a valid image is present, issue the boot flash: command in order to manually boot the switch from the image.
If a valid image is not present, issue the copy xmodem command in order to install an image to Flash from the switch: prompt.