Ethernet Switching
Ethernet Switching

Useful Steps to recover from a Loader prompt ( Loader>)

‎07-27-2016 07:37 AM

                                               Steps to recover from a Loader prompt ( Loader> )

There may be situations if a unit has failed to load the kernel during boot process and displays the below message:

can't load '/kernel' can't load '/kernel.old'

Press any key or space bar to enter into the loader prompt. < After pressing space bar or any key you would be directed to the below prompt >

Loader >

To recover from this situation, below procedure can be used.

  1. Format a USB stick with the FAT32 file system.
  2. Copy the desired JunOS image (*.tgz) to the USB Stick. Make sure that no file(s) is there in the USB drive before copying the Junos image.
  3. Insert the USB stick into the USB port on the switch.
  4. Connect via console port to the switch.
  5. Power on the switch.
  6. Press the space bar after getting the above message to get into the loader prompt.
  7. Type the command " loader> install file:///jinstall-ex-xxxx-xx.xxx.x-domestic-signed.tgz and press [enter]”. < Marked in BLUE is the Junos image file name copied in the USB>
  8. After the above command the switch would reboot and get you to the normal prompt.
  9. It would ask for User Name to get in. Type root as username and press [enter], it would give you the % prompt. There is a possibility that system would not accept the root as username, this would be in the case of old units where root-login is denied. Then there would be a need to recover the root password and there is a separate procedure for it.
  10. Above command (@ point 7 )will load the Junos in the switch but there is a possibility that switch may boot from the old partition having old version of image.
  11. Verify the same using # run show system snapshot media internal command. This command will show the Junos image present in both the partitions (In below image both have the same version).

12. If the unit has the updated/desired verison then skip the step number 13.

13. Run command # run request system reboot slice alternate to get the new version of Junos stored in alternate         partition, in case required.

14.  Now the new unit is ready to join the VC or master.

15. Make the connections and check the status of new unit . After this, the unit would get the configuration from master once joined in VC.

 

 

2 REPLIES 2
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Ethernet Switching

Re: Useful Steps to recover from a Loader prompt ( Loader>)

‎07-27-2016 08:14 AM

step 13 is not correct !!!! Take care you are requesting a reboot and start from the alternate partition !!!

 

13. Run command # run request system reboot slice alternate to get the new version of Junos stored in alternate         partition, in case required.

CORRECT is  # run request system snapshot slice alternate

 

regards

 

alexander

Ethernet Switching
Solution
Accepted by topic author gumberamit
‎07-28-2016 08:59 AM

Re: Useful Steps to recover from a Loader prompt ( Loader>)

‎07-27-2016 03:36 PM

This index kb explains all the various prompts that an EX switch might end up at when it fails to load Junos and provides links on how to correct that situation.

 

Can't get to the Loader Prompt (loader>) 
Loader Prompt ( loader >)
Debug Prompt (db>)
UBoot Prompt (=>)
Can't load kernel error
'Loading Junos' reported on LCD panel

 

EX switch – Troubleshoot upgrade failure/crash – System stuck on Boot-up

https://kb.juniper.net/InfoCenter/index?page=content&id=KB20464

Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
http://puluka.com/home