Install TWRP and Root on Fairphone 4 / iodéOS

TWRP

You have to use TWRP because iodéOS recovery doesn’t allow adb shell.
If you boot TWRP via fastboot boot twrp.img it gets stuck.
For some reason, you have to install it.

  • Install iodéOS and unlock bootloader

  • Enter bootloader:

      adb reboot bootloader
  • Get current slot:

      fastboot getvar current-slot
  • Install TWRP:

      fastboot flash recovery twrp-3.6.0_FP4-UNOFFICIAL-20211216.img
  • Enter TWRP:

      fastboot reboot recovery
  • “Mount” → “Disable MTP”

  • Extract boot image (replace [slot] with current slot):

    adb shell dd if=/dev/block/bootdevice/by-name/boot_[slot] of=/system/boot.img
    adb pull /system/boot.img
  • Reboot and copy boot.img to sdcard:

      adb push boot.img /sdcard
  • Patch boot.img with Magisk app

  • Transfer / adb pull that patched boot.img to your PC

  • Follow root guide

Root

  • Unlock bootloader (will reset your phone)
  • Reboot to bootloader: adb reboot bootloader
  • Boot patched boot image:
  • fastboot boot patched_boot.img
  • Open the Magisk app
  • Cancel “Requires Additional Setup”
  • Choose “Install” → “Direct Install” and “Reboot”
  • Your phone is now rooted, you can’t lock the bootloader again