Recovering From U-boot Mode
Have you ever found your Junos device stuck in the "U-boot" mode ( => ) before? Mario Costa explains how to recover from this situation.
When in this state your Junos image has of course "magically disappeared" and your heart skips an unhealthy beat. Here is a survival guide that will aid you in getting Junos installed from a TFTP/FTP server on your network.
Firstly, you need to get your environment variables set, which is basically assigning the following: Management Port IP address (ipaddr), Gateway IP address (gatewayip), TFTP/FTP Server IP address (serverip)
setenv ipaddr 192.168.1.1
setenv netmask 255.255.255.0
setenv gatewayip 192.168.1.254
setenv serverip 192.168.1.100
Secondly, reboot the device (boot command) to then access the "Loader" prompt. During the reboot process you will be presented with the following output:
Hit [Enter] to boot immediately, or space bar for command prompt.
After pressing the space bar key on your keyboard you gain access to the Loader prompt:
Thirdly, you need to install (via TFTPBOOT) the JunOS image on your device:
Wait patiently as the Junos device boots. After the boot process has completed successfully you should have Junos installed on your internal flash and a "healthy device" up and running again.