Install /e/OS on a Teracube - Teracube 2s (2025) sapphire

This guide installs /e/OS on your sapphire. Read it through once before you start, so you don’t hit surprises partway in. Downgrading from a newer OS version than the /e/OS build you’re about to install can cause instability or brick some devices — check your current OS version first. Flashing is done at your own risk: /e/OS builds are provided as best effort, without any guarantee, and the /e/OS project takes no responsibility for the consequences.

Requirements

• Back up your important data to an external storage device — some of the steps below format the phone, wiping any backup left on it.
• Charge your phone above 50%.
• Enable adb and fastboot on your PC — setup instructions.
• Download every file listed in the Downloads section below before you start.
• Use a real data cable — some cables only charge and can’t transfer data.
• Enable USB debugging on your device — instructions.
• Confirm your exact model in the Device Selector: where shown, hover the device name for the supported model number, and check it matches yours exactly.
• Boot the stock OS at least once and check everything works — SMS, calls, and both over WiFi and LTE if available (some devices need VoLTE/VoWiFi used once on stock to provision IMS). Whatever’s broken on stock stays broken on /e/OS.

Downloads for sapphire

Not sure which one to pick? See official vs. community builds.

Enabling USB debugging and OEM unlock

1. Connect device to a PC via USB-C cable
2. Enable Developer Options following the guide given here
3. Enable USB debugging option following the guide given here
   • Click on OK for Allow USB debugging? prompt
   • Click on Allow for Allow USB debugging? prompt showing computer’s RSA key fingerprint
4. Enable OEM Unlock option following the guide given here

Booting into fastboot and unlocking bootloader

1. Reboot to fastboot using either of two methods (Automatic or Manual)
   • Automatic
     • From your computer, run adb reboot bootloader
   • Manual
     • Turn off your phone and enter boot menu by holding volume up and power keys
     • The boot menu will present three options, press volume up until Bootloader is selected
     • Press power to accept this choice
2. Unlock the device with the following command
   • fastboot flashing unlock
3. Accept any prompts that may appear on device
4. If successful, it will show success message on PC and device
5. Reboot the device with the following command
   • fastboot reboot

Installing /e/OS

Windows users: run these commands in Git Bash, not in the default command prompt.

Let’s proceed with the installation:

1. Unzip the file you downloaded from the link in the Downloads for sapphire section above.

   unzip <fileyoudownloaded>
   

   Replace <fileyoudownloaded> with the name of the file you downloaded. You can also unzip it using a File Manager/File Explorer.

2. Confirm that the folder where you unzipped the files contains the following:

   • bin-linux-x86 directory - which contains linux tools including fastboot and adb
   • bin-msys directory - which contains Windows tools including fastboot and adb
   • bin-darwin directory - which contains MacOS tools including fastboot and adb
   • .img files - The .img files that are to be flashed onto the device.
   • flash_sapphire_factory.sh - The installer script.

3. Boot your sapphire into bootloader/fastboot mode:

   • With the device powered off
   • hold Volume Up + Power to open the menu. Use Volume Up and Volume Down to navigate and Power to select. Select Bootloader option

4. Open a terminal (Linux) or Git Bash (Windows) in the folder that contains flash_sapphire_factory.sh — right-click inside the folder and choose “Open terminal here” / “Open Git Bash here”. Then make the script executable and run it:

   chmod +x flash_sapphire_factory.sh && ./flash_sapphire_factory.sh
   

   The chmod step may require root/sudo privileges.

5. The device reboots automatically once all the required files have been installed.

Booting into fastboot and locking bootloader

1. Reboot to fastboot using either of two methods (Automatic or Manual)

   • Automatic

     • From your computer, run

       adb reboot bootloader
       

   • Manual

     • Turn off your phone and enter boot menu by holding volume up and power keys
     • The boot menu will present three options, press volume up until Bootloader is selected
     • Press power to accept this choice

2. Lock the device with the following command

   fastboot flashing lock
   

3. Accept any prompts that may appear on device

4. If successful, it will show success message on PC and device

5. Reboot the device with the following command

   fastboot reboot
   

Please share your experience , suggest tips or changes to this install guide documentation by visiting the Teracube 2s (2025) specific topic on our community forum. To report issues in /e/OS please refer this guide