[Help] Unbricking Your OnePlus 9RT After a Failed LineageOS 22 Flash: A Comprehensive Guide

Welcome to Magisk Modules, your trusted resource for all things Android customization. If you’ve found yourself in the dreaded fastboot loop after a failed LineageOS 22 installation on your OnePlus 9RT, fear not! This comprehensive guide will walk you through various recovery methods, whether you’re on Linux or Windows, and help you avoid turning that soft brick into a permanent hard brick. We understand the frustration of encountering issues while flashing custom ROMs, and we’re here to provide you with the knowledge and tools to get your device back up and running. This guide is designed to provide a more detailed, effective, and comprehensive solution than currently available online.

Understanding the Situation: OnePlus 9RT Stuck in Fastboot

The problem described involves a OnePlus 9RT (MT2111 - Indian variant) getting stuck in fastboot mode during a LineageOS 22 installation attempt. Specifically, the user encountered issues with fastboot wipe-super super_empty.img, followed by subsequent failures when attempting to flash other partitions like boot and dtbo. The phone remains detectable via fastboot devices, but all flashing attempts hang indefinitely. This situation, while alarming, is usually recoverable and considered a soft brick.

Preliminary Checks and Preparations

Before diving into advanced recovery methods, let’s ensure we’ve covered the basics:

Verifying USB Connectivity

Ensure you’re using a high-quality USB cable known to reliably transfer data. Faulty or damaged cables can interrupt the flashing process. Try different USB ports on your computer, preferably USB 2.0 ports as they sometimes offer better compatibility.

Confirming Fastboot Drivers (Especially on Windows)

On Windows, incorrect or outdated fastboot drivers are a common culprit.

Android SDK Platform-Tools

The most reliable way to get the correct drivers is through the Android SDK Platform-Tools. You can download them from the official Android developer website. After installation, ensure the platform-tools directory is added to your system’s PATH environment variable. This allows you to execute fastboot commands from any directory.

Google USB Driver

Install the Google USB Driver, also available through the Android SDK Manager or as a standalone download.

Driver Installation Procedure (Windows)

1. Connect your OnePlus 9RT in fastboot mode to your computer.
2. Open Device Manager (search for it in the Windows Start Menu).
3. Locate your phone, which may appear as “Android Device,” “Unknown Device,” or something similar with a yellow exclamation mark.
4. Right-click the device and select “Update Driver.”
5. Choose “Browse my computer for drivers.”
6. Navigate to the directory where you extracted the Google USB Driver or the platform-tools directory within the Android SDK.
7. Make sure the “Include subfolders” option is checked.
8. Windows should install the driver. If prompted with a security warning, accept it.

Verifying Fastboot Installation and Version

Ensure that fastboot is correctly installed and accessible from your terminal or command prompt. To verify, open a terminal/command prompt and type fastboot --version. You should see the version number of the fastboot tool. If not, revisit the Android SDK Platform-Tools installation steps. Using an outdated version of Fastboot can sometimes cause issues with newer devices. Consider updating to the latest version available in the SDK Platform-Tools.

Recovery Methods: Linux and Windows

Let’s explore recovery methods tailored for both Linux and Windows environments.

Linux Recovery Methods

1. Retrying Basic Fastboot Commands (With Modifications)

The initial attempts to flash failed, but let’s try again with some modifications to the commands:

• Flashing Boot and DTBO:

  fastboot flash boot boot.img
  fastboot flash dtbo dtbo.img
  

  Important: Ensure that the boot.img and dtbo.img files you are using are specifically designed for your OnePlus 9RT model (MT2111) and the exact version of LineageOS 22 you are attempting to install. Mismatched files are a common cause of boot issues. Verify checksums (MD5 or SHA256) of the files to confirm they are not corrupted.

• If the “Sending…” process still hangs:

  • Try using the --sparse option:

    fastboot flash --sparse boot boot.img
    fastboot flash --sparse dtbo dtbo.img
    

    The --sparse option can help with large files by breaking them into smaller chunks.

  • Lower the USB transfer speed using:

    fastboot --download-buffer size flash boot boot.img
    fastboot --download-buffer size flash dtbo dtbo.img
    

    Replace size with a smaller buffer size, such as 65536 (64KB) or 32768 (32KB). Experiment with different sizes to find one that works.

• Wiping Data and Cache: The original attempt to wipe data failed with “unknown command.” Let’s try a more specific approach:

  fastboot erase userdata
  fastboot erase cache
  

  If these commands still fail, it suggests a deeper problem with the partition table or fastboot itself.

2. Utilizing fastboot update (If Applicable)

If you have a complete LineageOS 22 zip file, you might be able to use the fastboot update command:

fastboot update lineageos-22-your_build.zip

This command attempts to flash all necessary partitions from the zip file. Note: This method is not always reliable and can sometimes lead to further complications. It’s generally recommended only if other methods have failed.

3. Trying Different Fastboot Binaries

Sometimes, specific fastboot binaries can have compatibility issues with certain devices. Try using different fastboot binaries from different sources (e.g., older versions of the Android SDK Platform-Tools or custom-compiled fastboot binaries).

4. Inspecting dmesg Output

While the flashing hangs, monitor the dmesg output in your Linux terminal:

dmesg -w

This command will display kernel messages in real-time. Look for any errors or warnings related to USB connectivity, device recognition, or storage access. These messages can provide valuable clues about the underlying problem.

5. Using a Different Linux Distribution (Live USB)

In rare cases, the issue might be related to specific configurations or drivers within your Fedora Linux installation. Create a bootable USB drive with a different Linux distribution (e.g., Ubuntu, Debian) and try the fastboot commands from that environment. This can help rule out OS-specific problems.

Windows Recovery Methods

1. Repeating Linux Steps in Windows

All the Linux recovery methods described above can also be attempted in Windows, after ensuring proper driver installation. Follow the same steps, substituting Linux terminal commands with Windows command prompt commands.

2. MSMDownloadTool (If Available – Research Thoroughly!)

You mentioned that the MSMDownloadTool is supposedly not available for the OnePlus 9RT. However, we strongly advise double-checking this information. Sometimes, tools or modified versions can be found in community forums or unofficial sources.

• Caution: Using unofficial MSMDownloadTool versions carries significant risk. Ensure you download from a trusted source and meticulously follow any instructions. Incorrect usage can permanently hard brick your device.
• Research: Spend ample time researching the availability of MSMDownloadTool for your specific OnePlus 9RT model (MT2111) and the associated risks. Look for verified success stories and detailed guides before attempting this method.

If you do find a reliable MSMDownloadTool, it’s generally the most effective way to recover from a hard brick. It completely reflashes the phone’s firmware, bypassing any corrupted partitions or bootloader issues.

3. QFIL/QPST (Qualcomm Flash Image Loader)

The OnePlus 9RT uses a Qualcomm Snapdragon processor. This opens the possibility of using Qualcomm’s flashing tools, QFIL (Qualcomm Flash Image Loader) which is part of the QPST (Qualcomm Product Support Tool) suite.

• Complexity: Using QFIL/QPST is more complex than using fastboot or MSMDownloadTool. It requires specific device configuration files (e.g., programmer file, rawprogram files, patch files) that are often difficult to obtain and require deep technical knowledge.
• Risk: Incorrectly using QFIL/QPST can easily hard brick your device. This method is only recommended for advanced users with experience in Qualcomm device flashing.
• Research: Thoroughly research the use of QFIL/QPST for the OnePlus 9RT. Look for detailed guides, verified configuration files, and understand the risks involved before attempting this method.

General Precautions to Avoid a Hard Brick

• Battery Level: Ensure your phone has sufficient battery charge (at least 50%) before attempting any flashing operations.
• Correct Files: Double and triple-check that you are using the correct files for your specific OnePlus 9RT model (MT2111) and the target ROM (LineageOS 22). Mismatched files are a primary cause of hard bricks.
• Stable Power: Use a stable power source for your computer to prevent interruptions during the flashing process.
• Avoid Interruptions: Do not disconnect the USB cable, power off your computer, or interrupt the flashing process in any way.
• Read Instructions Carefully: Meticulously read and understand all instructions before executing any commands.
• Backup (If Possible): While you’re already in a soft-bricked state, if you had a previous backup, keep it safe! If you can somehow boot into recovery (TWRP, if you had it installed), attempt a backup before proceeding further.
• Avoid Random Commands: Do not execute any fastboot commands you don’t fully understand.
• Seek Expert Advice: If you’re unsure about any step, seek advice from experienced users or developers in relevant online forums.

Specific Advice Related to fastboot wipe-super

The fastboot wipe-super command is intended to erase the super partition, which contains dynamic partitions. However, it can be risky, especially if the device’s partition table is already corrupted or if the command is not executed correctly.

• Alternatives: Before resorting to fastboot wipe-super, explore alternative methods for clearing space or resolving partition-related issues.
• Super Empty Image: When using fastboot wipe-super super_empty.img, ensure the super_empty.img file is specifically designed for your OnePlus 9RT and is compatible with the ROM you are trying to install. Using an incorrect or corrupted super_empty.img can lead to irreversible damage.
• Size Warning: The warning “skip copying super image avb footer (super partition size: 0, super image size: 5184)” indicates that the super partition size is being reported as zero. This is a red flag. It means that fastboot might not be able to correctly identify the size of the super partition, and wiping it could lead to data loss or corruption.

Advanced Troubleshooting Steps

1. Analyzing Partition Table (GPT)

If basic flashing commands fail, there might be an underlying issue with the partition table (GPT). This is more complex and requires specialized tools.

• GPT fdisk (gdisk): Use gdisk (GPT fdisk) on Linux to inspect the partition table. This requires booting from a live Linux environment and connecting your phone in fastboot mode.
• Caution: Modifying the partition table is extremely risky and can easily hard brick your device. This should only be attempted by experienced users who understand GPT partitioning.

2. Using EDL Mode (Emergency Download Mode)

EDL mode is a low-level flashing mode that bypasses the bootloader. It can be used to recover from severely bricked devices.

• Entering EDL: Entering EDL mode on the OnePlus 9RT typically involves shorting specific test points on the motherboard. This requires opening the device and using specialized tools (e.g., multimeter, tweezers).
• Risk: Incorrectly shorting test points can damage your device. This method is only recommended for experienced users with knowledge of electronics repair.
• Tools: Flashing in EDL mode usually requires specialized tools like QFIL/QPST and specific device configuration files.

Final Thoughts

Recovering from a soft brick can be a challenging process, but with patience, persistence, and the right tools, it’s often possible. Remember to prioritize safety, research thoroughly, and avoid any actions you’re not completely comfortable with. Always back up your data whenever possible, and seek help from experienced users if you get stuck. Good luck! Visit Magisk Module Repository for your one-stop shop for all your Magisk Modules.