How to recover from Boot Loop on Dell Networking C Series chassis switch.

Summary: How to recover from Boot Loop on Dell Networking C Series chassis switch.

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Instructions

This article discusses the steps needed to recover from an RPM boot loop on a Dell Networking Force10 switch.


Overview
 
  1. How to identify the behavior of the RPM
  2. What is needed to Resolve
  3. Steps to Resolve

How to identify the behavior of the RPM 
 
 
This is typically seen when upgrading or failing over an RPM that will not sync with the other RPM installed in the chassis.  You will console into the RPM in question and see that it never completes the boot process successfully.  The same partial boot text loops repeating.  The problem is the boot selector is not able to find a proper image to load.


What is needed to Resolve
 
  • Verify a new fresh download of the needed firmware version is saved in the flash directory of the switch.  If not possible to verify a new download can be prompted thru the boot_user mode options.
     
  • In boot_user mode the primary boot needs to point to valid bootable image in the flash directory.  If not, you can use FTP, TFTP to transfer the image by point the primary or secondary boot to use a FTP or TFTP device to retrieve the file during the next boot attempt.
     
  • A valid image .bin file is needed to in the root directory of the FTP or TFTP server device.  The management ethernet 0/0 port will need to be able to reach the IP address of the FTP TFTP server.  If this is not normally possible because of the network topology, you can set the management ethernet IP address and the default gateway in boot_user mode to all proper connectivity. 

 

 

NOTE: If a known easy network path is not available to FTP or TFTP server you can use a laptop with a transfer protocol server running and create a point to point connection plugging a cable directly from the laptop ethernet port to the management ethernet 0/0 port on the specific RPM. Then you would modify the laptop IP address and or the management ethernet port to allow same network IP communication thru the point to point connection.

 

 

Steps to Resolve

 
To access the BOOT_USER mode during the boot loop - When the prompt, "Hit any key to break into BOOT_USER mode" appears, press a key 

 

 

NOTE: Depending on the firmware version installed you may see different key strokes required to interrupt the boot. Some require hitting the Shift, Control and 6 keys at the same time.

 

 

Verify the current Boot Parameters by running the show bootvar command:
 
BOOT_USER # show bootvar

PRIMARY OPERATING SYSTEM BOOT PARAMETERS:
========================================
boot device                                                       : ftp
file name                                                           : /imagefilename.bin
Management Ethernet IP address                      : 10.1.1.1/24
Server IP address                                              : 10.1.1.200
username                                                          : username
password                                                          : ******
 
SECONDARY OPERATING SYSTEM BOOT PARAMETERS:
==========================================
boot device                                                        : flash
file name                                                            : /FTOS_CB_8.4.7.0.bin

DEFAULT OPERATING SYSTEM BOOT PARAMETERS:
========================================
boot device                                                        : flash
file name                                                            : /FTOS_CB_8.4.7.0.bin
 

Make note of the current boot devices listed for the Primary, Secondary and Default boot systems.  Also make note of the format of how the output is presented.  After you make changes the display of the boot device, file name etc… will need to have the same spacing and the colons need to be lined up in the right column.  If you do not clear and input the needed changes properly they will not line up in the columns.  This would indicate that you have extra spaces in the input.
 

 

NOTE: You cannot use Backspace to remove characters of spaces. To change the information, press the . (period) key and enter new information. After you enter the information, press Enter. You can also use the Shift+Backspace keys together to remove characters. You may need to use this option to back up all the way to the line above to verify no characters spaces are left unknowingly.


Use the interface management ethernet ip address command to change the ip address of the management 0/0 port on the RPM if needed to reach the FTP/TFTP server:
 

BOOT_USER# interface management ethernet ip address 10.1.1.1/24


Verify the IP address configuration:
 

BOOT_USER # show interfaces management ethernet
Management ethernet IP address: 10.1.1.1/24


Use the default-gateway command to set the needed default gateway to reach the transfer protocol server network:
 

BOOT_USER# default-gateway 10.1.1.200
 

Verify the default-gateway configuration:
 

BOOT_USER # show default-gateway

Gateway IP address: 10.1.1.200

 

NOTE: input a "no" in front of the above commands in order to remove.

 

Change the Primary and or Secondary Operating System Boot Parameters:
 

BOOT_USER # boot change {primary | secondary | default}
 

primary - Enter the keyword primary to configure the boot parameters used in the first attempt to boot FTOS.

secondary -  Enter the keyword secondary to configure boot parameters used if the primary operating system boot selection is not available

default -  Enter the keyword default to configure boot parameters used if the secondary operating system boot parameter selection is not available.  The default location should always be the internal flash device (flash:) and a verified image should be stored there.

 

NOTE: This can be tricky to enter the information properly. You will need to use "Shift + Backspace" keys to backup and delete all possible character entries before entering new information. If not the information is not configured properly. As a result the display of the information is not shown properly.  You should see all the colons in the right hand column lined up straight.  If not, you have extra characters that need to be deleted.

 
You must see the details displayed in the same format as below where the configured details are displayed with the colons all lined up in the right hand column.


BOOT_USER # boot change primary

'.' = clear field; '            -' = go to previous field

boot device                                   : ftp
file name                                      : /imagefilename.bin
Server IP address                         : 10.16.1.209
username                                     : username
password                                      : ******

BOOT_USER #

 

NOTE: The file name location is pointing to the FTP root directory. If you have the image file at a different location that will need to be specified.

 


 

Affected Products

C7004/C150 Aggregation Core chassis Switch, C7008/C300 Aggregation Core chassis Switch
Article Properties
Article Number: 000122551
Article Type: How To
Last Modified: 16 Oct 2025
Version:  5
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