Creating a USB key for installing TufinOS on an appliance

In order to install TufinOS on a Tufin appliance, you must boot from a USB key that has the TufinOS image on it.

Prerequisite

An empty USB flash drive with at least 32GB of space.
A TufinOS image file. The image file can be obtained from the Download Center in the Customer Portal.

To prepare the USB key

Copy the compressed image to a Linux machine.
Verify the integrity of the downloaded compressed file. Run a checksum tool on the .tgz file and make sure that the output matches the checksum in the matching documentation item in the Download Center.
Decompress the downloaded file:
```
tar xzvf TufinOS-X.XX-XXXXXX-x86_64-XXXX-Final.usb.img.tgz
```
tar xzvf TufinOS-X.XX-XXXXXX-x86_64-XXXX-Final.usb.img.tgz
After decompression, you will have two files - the main .img file and a .sha256 checksum file.
Verify the integrity of the TufinOS image using the checksum file:
```
sha256sum -c TufinOS-X.XX-XXXXXX-x86_64-XXXX-Final.usb.img.sha256
```
sha256sum -c TufinOS-X.XX-XXXXXX-x86_64-XXXX-Final.usb.img.sha256
Connect the USB flash drive to the Linux server.
Run the command:
```
dmesg | tail
```
dmesg | tail
At the end of the output of this command you will find the USB drive device name. Usually it is /dev/sda, /dev/sdb, or /dev/sdc. Copy that name.
Erase the USB flash drive before burning the TufinOS image to the USB flash drive:
```
dd if=/dev/zero of=/dev/<usb flash drive device name> bs=512
```
dd if=/dev/zero of=/dev/<usb flash drive device name> bs=512
Burn only the decompressed TufinOS image file to the USB flash drive:
```
dd if=TufinOS-X.XX-XXXXXX-x86_64-Final.usb.img of=/dev/<usb flash drive device name> bs=512
```
dd if=TufinOS-X.XX-XXXXXX-x86_64-Final.usb.img of=/dev/<usb flash drive device name> bs=512
Where <usb flash drive device name> is the name copied in previous step. This step may take a while; about 60 seconds or less.
Flush the data to the disk to make sure that all data is copied correctly.
```
sync ; sync
```
sync ; sync
Remove the USB key from the machine.

After TufinOS is installed, you can transfer the TOS installation file to the appliance and install it.

TufinOS 3: /opt
TufinOS 4: /opt/misc/