Technical Tip: Format FortiGate firmware using a TFTP server in MacOS

1. Copy the FortiGate firmware image to TFTP directory:

cp /path/to/fortigate_firmware.out /private/tftpboot/

Note: The default TFTP directory on macOS is /private/tftpboot, but any directory can be used. Here 'fortigate_firmware.out' is the name of the image file downloaded.

If the error 'permission denied' appears, use the following command:

sudo cp /path/to/fortigate_firmware.out /private/tftpboot/

2. Set permissions to ensure the TFTP server can access the files:

chmod -R 777 /private/tftpboot/

Remember to change the permissions back later:

chmod -R 755 /private/tftpboot/

3. Disable MacOS Firewall: Navigate to System Settings -> Network -> Firewall -> Turn Off (remember to enable it again later).

4. Start TFTP server:

sudo launchctl start com.apple.tftpd

5. Verify TFTP is running and listening on port 69 (udp 0 0 *.69):

sudo netstat -an | grep 69

6. Connect an Ethernet cable from the macOS computer to the FortiGate WAN1 port (or another Ethernet port).

Assign a static IP address to the Ethernet interface: Go to System Settings -> Network -> Ethernet -> Details.

Set 'Configure IPv4' to Manual:

• IP Address: 192.168.1.100
• Subnet Mask: 255.255.255.0

7. From the macOS Terminal, test connectivity to the TFTP server:

tftp 192.168.1.100 tftp> get fortigate_formware.out tftp> quit

8. Connect to the FortiGate console port using PuTTY on macOS:

Connect the Serial to the USB adapter to the PC.

Open a terminal and list available serial ports: 

ls /dev/*usb*

Find a device like /dev/tty.usbserial- (e.g., /dev/tty.usbserial-A9XBSOU6). Note this name: it is the serial port for PuTTY.

Open PuTTY and use the following settings:

9. Follow the instructions from step 9 onwards in Technical Tip: Formatting and loading FortiGate firmware image using TFTP.