Recovering from a Failed Software Upgrade on an EX-series Switch
If the JUNOS software loads but the CLI is not working for any reason, or if the switch has no software installed, you can use this recovery installation procedure to install the JUNOS software.
If there is already a JUNOS image on the system, you can either install the new JUNOS package in a separate partition and both JUNOS images will remain on the system, or you can wipe the disk clean before the new installation proceeds.
To perform a recovery installation:
- Power on the switch. The loader script starts.
- After the Loading /boot/defaults/loader.conf displays, you are promptedwith:
Hit [Enter] to boot immediately, or space bar for command prompt.
Hit the space bar to enter the manual loader. The loader> prompt displays.
- Enter the following command:
install [––format] source
Where:
- Include the ––format option if you want to wipe the internal disk before installing the software package. If you do not include this option, the system installs the new JUNOS software package in a different partition from any existing JUNOS software package.
-
source represents the name and location
of the JUNOS software package either on a server on the network or
as a file on an external USB drive:
- Network address of the server and the path on the server. For example, tftp://192.17.1.28/junos/jinstall-ex-9.0R1-domestic.tgz
- The JUNOS package on a USB device is commonly stored in the root drive as the only file. For example, file:///jinstall-ex-9.0R1-domestic.tgz
- The installation proceeds as normal and ends with a login prompt.
The system disk has two partitions and can have a different software package installed in each partition. You can manually reset the system to boot from the other partition. You can set the system to boot from the other partition on the next reboot only, or make the change permanent so that it will boot from the other partition on all subsequent reboots.
To specify reboot from the partition that is not currently active for the next reboot only, issue the following commands from within the loader:
- set currdev=disk0Sdisk-number:, where disk-number indicates the partition number, either 1 or 2.
- boot
To reset the partition that is designated the active partition, exit the CLI and enter the following commands from the UNIX prompt:
- # echo "adisk-number" |fdisk –f –/dev/da0, where disk-number indicates the partition number, either 1 or 2.
- # reboot




