View source for Loading a configuration onto a JunOS device

* Copy your config file to a FAT32 formatted USB thumb drive (the drive ''must'' contain exactly one partition that stretches over the whole device)
* Boot up the Juniper device and connect to its serial console 
* You should see a <code>root></code> prompt
** (If, right after login, you already are in shell mode (<code>root@%</code>) and the <code>exit</code> command will only log you out instead of bringing you into command mode (<code>root></code>), you can issue the <code>cli</code> comamnd to get there.)
* Type <code>start shell</code> to get the <code>root@%</code> prompt
* Create a mount directory: <code>mkdir /mnt/usb</code>
* Plug in the USB drive and mount it: <code>mount -t msdosfs /dev/da1s1 /mnt/usb</code>
* Type <code>exit</code> to exit the shell
* From the <code>root></code> prompt enter <code>configure</code> to get into config mode (you'll see a <code>root@#</code> prompt)
* Variant A:
** Use the following command to load the configuration: <code>load override /mnt/usb/<config file name></code>
* Variant B:
** Type <code>load override terminal</code> to paste in configuration commands (the Cisco way)
** Type [ENTER] and the [Ctrl-D] to exit load mode
* Type <code>commit</code> to activate the loaded configuration and exit config mode with the <code>exit</code> command
* Unmount the USB drive (<code>umount /mnt/usb</code> in shell mode) before unplugging it