Install on Pixel 4a
From a Windows computer
- Prepare your Android device
- Prepare your host computer
- Install CalyxOS
- Back to Stock
- Security Notes
Install / Pixel 4a / Windows
- 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 Windows 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
Install USB drivers for Windows
Windows requires specific USB drivers in order for device-flasher to work.
Download Google USB Driver
Open that page, click Click here to download Google USB Driver ZIP file, then accept the terms and conditions. Save the ZIP file to your host computer.
- Put your Android device in Fastboot mode.
- Connect your Android device to your computer’s USB port.
- On the Windows computer, open the Device Manager
(windows key + X, select Device Manager from the list)
- Expand the list item Other Devices
Not there? Make sure the Android device is plugged in and in Fastboot mode.
- Right-click the name of the device you connected, and then select Update Driver.
- In the Hardware Update wizard, select Browse my computer for driver software and click Next.
- Click Browse and then locate the USB driver ZIP file.
- Click Next to install the driver.
For more information, see Android developer site.
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:
CertUtil -hashfile device-flasher.exe SHA256
And ensure the result says
87b719cb217b3dba69f061da0c3e5ce6ebabea81e15394ca4c36b584b5b3f19d. 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 Pixel 4a (sunfish). 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:
CertUtil -hashfile sunfish-factory-22307002.zip SHA256
And ensure the result says
614b3a66ebea598f2e34d30dde581fa9554cc73db6cf19ef1d8e7fde41185933. 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
device-flasher to run it.
Your anti-virus may falsely flag device-flasher as infected. This is because the program is written in the Go programming language, see the Go FAQ for more information.
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 6 Pro, 6, 5a (5G), 4a (5G), 5, 4a, 4 XL, 4, 3a XL, 3a contain the full security patch, as they are still being updated by Google.
- End-of-life: The Pixels 3 XL, 3, 2 XL, 2 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.
- End-of-life: The Xiaomi Mi A2 is no longer being updated by Xiaomi, so the CalyxOS releases for it 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. Additionally, due to a Xiaomi bug wherein updating causes the device to get wiped, we have to ship the September 2020 firmware.