How to install Juniper OS Step by Step (Successfully Tested on Ex2200) ,How to mount a USB drive on the EX/J/SRX/MX series ?

Insert the USB drive to Juniper device. USB drive must be formatted by FAT32. NTFS will
be not mount.

When you insert USB drive, a new partition will show you like:
da1
da1s1

Step3
root@% ls /dev/
[Here you can see the all partition of HDD also a new partition will arrise here]

Step4
root@:RE:0% mount_msdosfs /dev/da1s1 /mnt/
[You need to mount your USB drive to /mnt directory. Here my new USB partition is da1s1,
It can be diffrent for depend on hardware]

Step5
root@:RE:0% ls /mnt/

jinstallex330011.4R2.14domesticsigned.tgz

[Your USB mount is completed to /mnt. You can see with above command]

Step6
root@:RE:0% cp /mnt/jinstallex330011.4R2.14domesticsigned.tgz /var/tmp/

[Copy the Juniper OS file to /var/tmp directory]

Step7
root@:RE:0% ls /var/tmp/
.snap
ex_autod_config
ex_autod_rollback_cfg
grestp
ifrtsdb
jinstallex330011.4R2.14domesticsigned.
tgz
krt_gencfg_filter.txt
rtsdb

[Confirm with above command to copy of file is finished or not]

Step8

root@:RE:0% umount /mnt/
root@:RE:0% umass1: at uhub1 port 1 (addr 2) disconnected

(da1:umasssim1:
1:0:0): lost device
(da1:umasssim1:
1:0:0): removing device entry
umass1: detached

[Now you can unmount to USB dribe. After above command you can remove your USB
Drive from your device]

Step9
root@:RE:0% cli
root@> request system software add /var/tmp/jinstallex330011.4R2.14domesticsigned.
tgz no-copy no-validate-reboot

[With this comand instalation process will be start] [nocopy mean after instalation JUNOS it will remove the current OS file from /var/tmp]

[Reboot mean after instalation JUNOS it will be reboot autamatically otherwise it will ask for
yes/no]