How to Fix – Force10 S4810 Switch Stuck in Boot Loop

In this blog I discuss how to fix a common boot loop problem. A boot loop can occur if you change the boot variables for a switch and accidentally put in incorrect information. You may also make a typo when telling the switch which FTOS image to load. Then when the switch reloads, it will attempt to load the non-existent FTOS image. On the S4810 [FTOS 8.3.7.0], if the “primary_image” fails to load, it will try the “secondary_image” and lastly the “default_image”. If all three boot variables fail to load an image, the switch goes into a boot loop where it keeps retrying to load the images from “primary_image” to “default_image”.

To break out of the loop, hit any key when the following line appears on the console: “Hit any key to stop autoboot:”. At this point you are in “u-Boot” mode. From here you can change the respective variables so that your switch is able to boot up. If your not sure what the variables and respective values you can set are, use the “printenv” and “help” commands to assist you. “printenv” will display the current values of all variables.

Below, I tell the switch on reload to boot the correct and more recent FTOS image from a TFTP location I have setup. It is very important that you use the “save” command before using the “reset” command to restart the switch.

– setenv primary_boot f10boot tftp://10.11.11.171/FTOS-SE-8.3.7.1.bin

– setenv default_boot f10boot tftpboot 10.11.11.171:FTOS-SE-8.3.7.1.bin

– setenv ipaddr 10.11.11.10

– setenv gatewayip address 10.11.11.254

– save

– reset