Install on Fairphone 4
From a Linux computer
- Prepare your Android device
- Prepare your host computer
- Install CalyxOS
- Back to Stock
- Security Notes
Install / Fairphone 4 / Linux
- Factory Image: This is a zip file that contains the entire CalyxOS operating system to be installed on your device.
- Flashing: On Android devices, installing a new operating system is called “flashing,” because it writes a new factory image to the device’s flash memory.
- Android Device: The device that you are installing CalyxOS on to.
- Host Computer: The Linux computer used to send commands to the Android Device. You will connect this computer to the Android device and run device-flasher to install CalyxOS.
- Fastboot: A mode of the Android device needed to install a custom Operating System. At various stages, you will be asked to put your Android device in Fastboot mode.
Prepare your Android device
There are a few things you must do to prepare your device to accept a new operating system:
Enable Developer Options
Settings → About Phone → tap Build number 7 times
Enable USB debugging
Settings → System → Advanced → Developer Options → USB Debugging
Enable OEM Unlocking
Settings → System → Advanced → Developer Options → OEM unlocking
This step might fail if there is no internet connection. In that case, connect to a WiFi network and remove SIM card, then try again.
Prepare your host computer
The device-flasher program needs certain udev rules installed. The device-flasher will set these rules up for you, but it may ask for your sudo password to do so. Alternately, you can install one of the following packages to correctly set the udev rules in advance.
Debian, Ubuntu, & derivatives:
sudo apt update sudo apt install android-sdk-platform-tools-common
Fedora & derivatives:
sudo dnf install android-tools
sudo pacman -S android-udev
sudo zypper install android-udev-rules
Save this executable to a new directory, where you will also later save the CalyxOS image.
This is an optional step, useful for ensuring you have the correct device-flasher executable. Open a terminal on your host computer, change to the directory where you saved device-flasher, and then run:
And ensure the result says
9c78801a2c54b93bb9f1fca686de791e694a952e954d99afdd25f441d47c38ad. This is the unique digest of the device-flasher. If it doesn’t match, then you have a corrupted or incorrect file.
Download factory image
Download CalyxOS Image
Save this image in the same directory as device-flasher. This image will only work for Fairphone 4 (FP4). Any attempt to install this image on a different device model may brick (destroy) the Android device.
Do not extract or rename the zip, simply copy it as-is.
Once downloaded, the next step is to verify the image. This step is optional, but verification helps ensure that you downloaded the image correctly, and that you got the correct image.
To verify the image, open a terminal window on the host computer where you saved the image and run the command:
And ensure the result says
5fbd640deeafa40d5e455ec6d4e0be883778327c33528a71ace41290a085f536. This is the unique digest of the image file. If it doesn’t match, then you have a corrupted or incorrect file.
For the highest level of confidence, you can optionally download the signature file and then verify image signature.
Now you are ready to install. Ensure that both the CalyxOS image and device-flasher are in the same directory.
Step 1. Connect the USB cable between the computer and the Android device.
Step 2. Run device-flasher
Open a terminal, change to the directory with the firmware image, and run:
chmod +x device-flasher.linux ./device-flasher.linux
Unlock the bootloader
At some point in the installation process, it will ask you to unlock the bootloader.
NOTE: if the bootloader is already unlocked, you will not see the unlock bootloader menu and installation will proceed automatically without you needing to touch anything.
The bootloader unlock menu looks like this:
Press a volume key to select UNLOCK THE BOOTLOADER option. Then press the power key to activate that option.
Once device-flasher is finished, you should now have a fully functional CalyxOS device. If not, please see our Community page for where you can post your questions.
Error running device-flasher
If you get a mysterious error when running device-flasher, or if device-flasher hangs, it may be a USB problem. Try connecting to a different USB port on your computer (yes, not all USB ports are created equal) or a different USB cable.
How do I tell if the bootloader is locked?
In Fastboot “Device State: locked” means the bootloader is locked.
On the initial boot screen, you may also see this if the bootloader is unlocked:
The bootloader is unlocked and software integrity cannot be guaranteed. Any data stored on the device may be available to attackers. Do not store sensitive data on the device.
Back to Stock
If you would like to return to the default operating system, please see Back to Stock Android.
- Over-the-air Updates: CalyxOS updates are delivered over-the-air (OTA) automatically, without any manual intervention needed. However, if you'd like to manually update your CalyxOS install, see OTA.
- Security Updates: The Pixels 7 Pro, 7, 6a, 6 Pro, 6, 5a (5G), 4a (5G), 5, 4a contain the full security patch, as they are still being updated by Google.
- Security Updates: The Fairphone 4 stock OS follows a different security update release schedule, which usually lags behind by a month or two compared to Pixels. The CalyxOS releases for it only contain the latest fixes to the open source components, such as the OS code and the Linux kernel. Proprietary components such as the bootloader, modem firmware, and other firmware get updates as soon as the stock OS update is available.
- End-of-life: The Pixels 4 XL, 4, 3a XL, 3a, 3 XL, 3 are no longer being updated by Google, so the CalyxOS releases for these devices only contain the fixes to the open source components, such as the OS code and the Linux kernel. Proprietary components such as the bootloader, modem firmware, and other firmware no longer get updates.