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MacCheck Troubleshoot - Operating T2 Chip MacBook | Phonecheck Help Center

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

Introduction

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

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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 top most 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.
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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.
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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.