Install OkcarOS on
Fairphone 4

FP4

WARNING: The provided instructions are for OkcarOS 20. These will only work if you follow every section and step precisely.
Do not continue after something fails!

Basic requirements

Read through the instructions at least once before actually following them, so as to avoid any problems due to any missed steps!
Make sure your computer has adb and fastboot. Setup instructions can be found here.
Enable USB debugging on your device.
Make sure that your model is actually listed in the “Supported models” section here (exact match required!)
Boot your device with the stock OS at least once and check every functionality.
WARNING: Make sure that you can send and receive SMS and place and receive calls (also via WiFi and LTE, if available), otherwise it won’t work on OkcarOS either! Additionally, some devices require that VoLTE/VoWiFi be utilized once on stock to provision IMS.
LineageOS is provided as-is with no warranty. While we attempt to verify everything works you are installing this at your own risk!

Unlocking the bootloader

NOTE: Unlocking the bootloader only needs to be done once per device.

WARNING: Unlocking the bootloader will erase all data on your device! Before proceeding, ensure the data you would like to retain is backed up to your PC and/or your Google account, or equivalent.

Follow the instructions at Fairphone Support to unlock your bootloader.

Installing a custom recovery using `fastboot`

Download Lineage Recovery. Simply download the latest recovery file, named recovery.img.
Important: Other recoveries may not work for installation or updates. We strongly recommend to use the one linked above!
Connect your device to your PC via USB if it isn’t already.
If your device isn’t already in fastboot mode, on the computer, open a command prompt (on Windows) or terminal (on Linux or macOS) window, and type:
```
adb -d reboot bootloader
```
You can also boot into fastboot mode via a key combination:
- With the device powered off, hold Volume Down + Power.
Once the device is in fastboot mode, verify your PC finds it by typing:
```
fastboot devices
```
If you don’t get any output or an error:
- on Windows: make sure the device appears in the device manager without a triangle. Try other drivers until the command above works!
- on Linux or macOS: If you see no permissions fastboot try running fastboot as root. When the output is empty, check your USB cable (preferably use a USB Type-A 2.0 one or a USB hub) and port!
Tip: Some devices have buggy USB support while in bootloader mode, if you see fastboot hanging with no output when using commands such as fastboot getvar ..., fastboot boot ..., fastboot flash ... you may want to try a different USB port (preferably a USB Type-A 2.0 one) or a USB hub.
Flash recovery onto your device:
```
fastboot flash recovery recovery.img
```
Now reboot into recovery to verify the installation.
- Use the menu to navigate to and to select the Recovery option.
NOTE: If your recovery does not show the OkcarOS logo , you accidentally booted into the wrong recovery. Please start at the top of this section!

Installing OkcarOS from recovery

Download the OkcarOS installation package that you would like to install or build the package yourself.
- (Optionally): If you want to install Google Apps add-on package (use the arm64 architecture), you can download it from here.
If you are not in recovery, reboot into recovery:
- With the device powered off, hold Volume Down + Power, then select “Recovery mode” using Volume keys.
Now tap Factory Reset, then Format data / factory reset and continue with the formatting process. This will remove encryption and delete all files stored in the internal storage, as well as format your cache partition (if you have one).
Return to the main menu.
Sideload the OkcarOS .zip package but do not reboot before you read/followed the rest of the instructions!
- On the device, select “Apply Update”, then “Apply from ADB” to begin sideload.
- On the host machine, sideload the package using: adb -d sideload filename.zip.
  Tip: Normally, adb will report Total xfer: 1.00x, but in some cases, even if the process succeeds the output will stop at 47% and report adb: failed to read command: Success. In some cases it will report adb: failed to read command: No error or adb: failed to read command: Undefined error: 0 which is also fine.

Installing Add-Ons

NOTE: If you don’t want to install any add-on (such as Google Apps), you can skip this whole section!

NOTE: Add-ons aren’t signed with OkcarOS’s official key, and therefore when they are sideloaded, Lineage Recovery will present a screen that says Signature verification failed, this is expected, please click Continue.

WARNING: If you want the Google Apps add-on on your device, you must follow this step before booting into OkcarOS for the first time!

Even though you are already in recovery, click Advanced, then Reboot to Recovery
When your device reboots, click Apply Update, then Apply from ADB, then adb -d sideload filename.zip for all desired packages in sequence.

All set!

Once you have installed everything successfully, you can now reboot your device into the OS for the first time!

Click the back arrow in the top left of the screen, then “Reboot system now”.

NOTE: The first boot usually takes no longer than 15 minutes, depending on the device. If it takes longer, you may have missed a step, otherwise feel free to get assistance.

Get assistance

After you’ve double checked that you followed the steps precisely, didn’t skip any and still have questions or got stuck, feel free to ask on our subreddit or in #OkcarOS on Libera.Chat.

Install OkcarOS on Fairphone 4