… from a Linux station and with a quite clear documentation 🙂

Step 1: Prepare the phone

1. Enable Developer options: go into Settings > About and find the Build Number and tap on it 7 times.
2. Enable USB debugging: go to Settings > Developer Options and find the suitable option.
3. Enable root access: go to Settings > Developer Options > Root access, and enable root access for ADB.

Step 2: Connect the Fairphone with ADB

First get ADB and Fastboot. Command line tools is sufficient, you do not need the whole Android Studio.

1. Start abd server with sudo adb start-server
2. Connect the Fairphone to the computer, and verify its presence with adb devices -l

Step 3: Download TWRP

Grab the last .img file from the TWRP download page for FP2. Store it somewhere on your computer (say in Downloads directory).

Rename your file from twrp-x.y.z-t-FP2.img to twrp.img.

Step 4: Install and run TWRP

1. Reboot the phone on bootloader mode: adb reboot bootloader. The screens displays a black background with a white « Fairphone »  and « Powered by Android » at the bottom.
2. Copy the TWRP img file: sudo fastboot flash recovery twrp.img
3. Here is the tricky part, you’ll need at least three hands or be organized :
   • From your Linux console, type sudo fastboot reboot without hitting the Return key.
   • On the Fairphone, press Volume UP + Power (and keep it pressed until the phone reboots and you see the TWRP screen).
   • Hit the Return key.

Step 5: use TWRP

For example to make a backup or upgrade to LineageOS