First, complete all the steps from the article Fairphone 4 OS manual installation.

Ubuntu/Ubuntu-based (version 18.04.x and newer) process

1. Connect the Fairphone 4 (in Fastboot mode) to your computer using a USB-C certified data cable.
   • If it doesn't work on your computer, try to the following:
     1. Press simultaneously the keys Ctrl + Alt + T to open the terminal.
     2. Type sudo apt-get update and press the Enter ↩ key.
        • Type your system password if required.
     3. Type sudo apt-get install adb and press the Enter ↩ key.
        • Type your system password if required.
     4. Type sudo apt-get install mtp-tools and press the Enter ↩ key.
        • Type your system password if required.
2. Locate the archive you downloaded in the previous step, (usually in the Downloads folder).
   
   1. If you're using Chrome Browser, press simultaneously the keys Ctrl + J. A new tab called Downloads will open.
   2. Look for the last download, the name starts with FP4. Click on the text Show in folder.
      
      A new window will open.
3. Extract the archive
   • Using Ubuntu Archive Manager:
     1. Right-click on the archive, the name starts with FP4.
     2. Click on Extract Here to extract the archive.
        
4. Start the terminal and navigate to the folder you just created, the name also starts with FP4.
   • Using the Ubuntu GUI (Graphical User Interface):
     1. Right-click on the folder.
     2. Click on Open in Terminal. A new terminal window will open
5. In the terminal window type: sudo chmod +x flash_fp4_factory.sh and press the Enter ↩ key. Type your system password if required.
6. In the terminal window type: sudo ./flash_fp4_factory.sh and press the Enter ↩ key.
   Type your system password if required.
7. The following warning may appear:
   Type in Yes and Press the Enter ↩ key.
8. The script will now run for a couple of minutes like in the following picture.
   
   Once done, you will see the following picture.
   
   
   -IMPORTANT-
   It can take up to 15 min. Do NOT interrupt the process, it might damage the device!
9. Done, your phone is now up to date. Your phone will now reboot, finishing the system update for a few minutes. You can now safely unplug your Fairphone from your computer.
10. Once done, for safety reasons, we strongly advise you to lock your bootloader again. To do so, follow the instructions in the article Manage the bootloader.

If after reading the article you need more help, contact our Customer Support.