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MacCheck Troubleshoot - Operating T2 Chip MacBook

Intel Macbooks that have a T2 Chip may require the following unlock process to allow the ability to boot from an external drive

Updated over 3 months ago

Phonecheck T2 Unlocking Utility

Introduction

This process is designed to unlock T2-secured Mac devices that are locked and unable to boot from external media. Follow the steps below to successfully unlock your T2-locked device and perform diagnostics using PhoneCheck MacDiagnostics.


🔐 Macs with the Apple T2 Security Chip

💻 MacBook Pro

Year

Model

Model Identifier(s)

Model Number(s)

2018

13” and 15” Pro

MacBookPro15,2 / 15,1

A1989, A1990

2019

13” and 15” Pro

MacBookPro15,2 / 15,1

A1989, A1990

2019

16” Pro

MacBookPro16,1

A2141

2020

13” Pro

MacBookPro16,2 / 16,3

A2289, A2251

All MacBook Pros from 2018–2020 with Intel CPUs (excluding some 2020 base models) have the T2 chip.


💻 MacBook Air

Year

Model

Model Identifier

Model Number

2018

Retina Air

MacBookAir8,1

A1932

2019

Retina Air

MacBookAir8,2

A1932

2020

Intel Retina Air

MacBookAir9,1

A2179

All Retina MacBook Airs from 2018–2020 with Intel CPUs include the T2 chip.


🖥️ iMac & iMac Pro

Year

Model

Model Identifier

Model Number

2017

iMac Pro

iMacPro1,1

A1862

2020

iMac (Intel, Retina 5K)

iMac20,1 / 20,2

A2115

⚠️ Standard 2017 and 2019 iMacs do not have the T2 chip.


🖥️ Mac Mini

Year

Model

Model Identifier

Model Number

2018

Mac Mini (Intel)

Macmini8,1

A1993


🖥️ Mac Pro

Year

Model

Model Identifier

Model Number

2019

Mac Pro (Intel Tower)

MacPro7,1

A1991


❌ Macs Without T2 Chip

  • Any pre-2018 Macs (except the 2017 iMac Pro)

  • M1 and M2 Macs (use integrated Secure Enclave in Apple Silicon)



Pre-requisites

Before you begin, ensure that:

  • The Mac device is T2-locked, without an operating system present.

  • An external disk with an OS cloned from PhoneCheck USB Cloner is connected to the Mac for the utility to run.

  • You have access to the Mac's Terminal and Disk Utility.

Step-by-Step Instructions

1️⃣ Connect the USB Drive

  • Plug the USB drive into the Intel MacBook
    (Make sure that the USB Drive was cloned using an Intel Mac)

2️⃣ Boot Into Recovery Mode

  • Restart the Mac and hold Command (⌘) + R until the Apple logo appears.

3️⃣ Erase the Internal Drive

  1. Select Disk Utility from the recovery menu.

  2. In the top-left corner, click View → Show All Devices.

  3. Select the topmost internal drive (usually labeled as Apple SSD).

  4. Click Erase.

  5. IMPORTANT - Name the internal drive anything other than "mac" (e.g., "internal", "main", etc.).

  6. Choose APFS and GUID Partition Map, then confirm to erase.

  7. Once erased, close Disk Utility.



4️⃣ Run the Unlock Script

  1. From the Recovery Menu, choose Utilities → Terminal.

  2. Enter the following command exactly:

    /Volumes/mac/Users/phonecheck/phonecheckT2Unlocker

    🔎 Note: If your external drive is not named "mac", adjust the path accordingly.

  3. Press Enter to run the script.

5️⃣ Wait for Completion

  • A progress % will appear (typically takes 6–8 minutes).

  • Once finished, you’ll be prompted to restart.

6️⃣ Restart and Remove USB

  • When prompted, press Y to confirm restart.

  • IMPORTANT: As soon as the Mac starts restarting, remove the USB drive to avoid boot loops or black screens.

7️⃣ Initial macOS Setup to the Home Screen

  • After reboot, you may be prompted to connect to Wi-Fi.

  • When asked for a password, enter: 1234.

  • Once logged in, do not run diagnostics (See Image) if the MacDiagnostic program launches.

  • Wait until the Mac Diagnostic application has fully loaded, then shut down the computer.


8️⃣ Adjust Startup Security

  1. Restart into Recovery Mode again (Command + R), without the USB drive connected.

  2. From the menu bar, go to Utilities → Startup Security Utility.

  3. When prompted for login:

    • Select Admin account

    • Password: 1234

  4. Change the settings to:

    • No Security

    • Allow booting from external or removable media

9️⃣ Boot from USB Drive

  1. Plug the USB drive back in.

  2. Click the Apple logo → Restart.

  3. Hold Option (⌥) key during restart.

  4. Select the external USB drive (orange icon).

  5. Proceed with booting into the USB environment.


⚠️ Important Reminders

  • Always remove the USB drive immediately after the first restart to avoid errors.

  • Please don't run diagnostics until the full unlock process is complete.

  • If any step fails, repeat from Step 2 and double-check drive names and script paths.

Troubleshooting

If you encounter any issues during the unlocking process, please check the following:

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