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One area of expertise that I have not yet shared on this blog is Android smartphone repair services. This post marks the beginning of documenting and sharing practical knowledge from my work providing technical assistance to people in need.

I have long considered writing about Android service topics, especially account Unlock methods—commonly known as Unlocking Google accounts, Mi accounts (for Xiaomi devices), as well as pattern or PIN locks. However, I hesitated for a while, unsure whether such content would attract meaningful traffic to the blog.

After keeping this idea to myself for some time, I finally decided to act on my curiosity. About three days ago, I even started a new blog dedicated to account Unlock topics. Still feeling uncertain, I decided to put that project on hold temporarily and share this guide here instead.

Let’s focus on the topic of this article: how to Unlock the pattern lock (and PIN) on the Vivo Y91. I performed this procedure just last night, so the steps are still fresh in my mind and easy to document clearly.

Note: This guide is intended solely for the legitimate owners of devices who have forgotten their passwords or personal Google account details. This procedure will erase all data on the phone. Please use this information responsibly.

Important Prerequisites & Safety Notes

Before proceeding, please read these critical points carefully:

• Data Loss Warning: This process will erase all user data on your Vivo Y91, including photos, videos, contacts, apps, and settings. Your device will be restored to the factory default state.
• Legal & Ethical Use: This guide is intended for legitimate owners who have forgotten their lock screen credentials or purchased a second-hand device that is locked. Unauthorized access to devices that do not belong to you is illegal and unethical.
• Technical Risks: Improper execution may cause software issues, including boot loops or permanent device damage. Proceed at your own risk.
• google account verification Awareness: After resetting the device, Google’s Factory Reset Protection (google account verification) will activate automatically. This means you will need to verify the original Google account previously synced on the device. This guide also covers how to Unlock google account verification for legitimate cases.

What You Need to Prepare

First, gather the following files and tools:

• eMMC Firehose Program File for Vivo Y91: This file can be extracted from the official Vivo Y91 flash ROM (master ROM file).
• Tweezers: For performing the test point method to enter EDL (Emergency Download) mode.
• QFIL (Qualcomm Flash Image Loader) – for erasing the userdata partition
• RBSoft Mobile Tool – for Unlocking google account verification Google account
• USB Cable: Good quality data cable to connect the phone to your computer.
• Computer/Laptop: With Qualcomm USB drivers installed. If you haven’t installed these drivers yet, search for "Qualcomm HS-USB QDLoader 9008 driver" on Google and install them first.

Download Links
• eMMC Firehose file for Vivo Y91
• QFIL Tool
• RBSoft Mobile Tool

How to Unlock Pattern Lock, PIN & google account verification Google Account on Vivo Y91 (Step-by-Step Guide)

Step 1: Disassemble the Vivo Y91 & Enter EDL Mode via Test Point

Power off your Vivo Y91 completely.

Carefully remove the back cover: Be very cautious! The Vivo Y91 has a fingerprint sensor attached to the back cover via a flexible cable. Do not pull the cover forcefully; gently disconnect the fingerprint flex cable first to avoid damaging it.

Perform a test point to enter EDL mode: Using tweezers, short the designated test points on the motherboard while simultaneously connecting the phone to your computer via a USB cable.

• Note: If you are unfamiliar with what test points are or how to perform this method, please search for "Vivo Y91 test point EDL mode" on Google for visual references. I forgot to document this specific step with photos during my process.

Verify EDL connection: Once successfully connected in EDL mode, open Device Manager on your computer and expand the Ports (COM & LPT) section. You should see "Qualcomm HS-USB QDLoader 9008" listed there. This confirms your phone is properly detected.

Step 2: Unlock Pattern/PIN Lock Using QFIL Tool

1. Open QFIL Tool on your computer.
2. Select the "Flat Build" option.
3. Click "Browse" next to "Select Programmer" and choose the eMMC Firehose file for Vivo Y91 that you downloaded earlier (I placed mine on the Desktop for easy access).
4. Click on the "Tools" menu at the top, then select "Partition Manager".
5. A confirmation dialog will appear – click "OK".
6. The Partition Manager window for Vivo Y91 will open, displaying all partitions on the device.
7. Scroll down the partition list until you find the "userdata" partition.
8. Right-click on "userdata" and select "Manage Partition Data".
9. A new dialog box will appear – click the "Erase" button.
10. A confirmation prompt will show up – click "Yes" to proceed.
11. The tool will now erase the user data partition. You will see a notification saying "Finish Erase Data Block" once the process is complete. This step effectively removes the pattern lock, PIN, or password that was set on the device.
12. 12. Close all dialog boxes in QFIL. If a notification appears saying "Phone Will Reset the EDL Mode", simply click "OK".
13. Disconnect the USB cable from your phone.

Step 3: First Boot & Wipe Cache Partition

1. Power on your Vivo Y91. At this stage, the phone may appear to be stuck on a blank screen or in a boot loop – do not panic! This is normal after erasing the userdata partition. Wait patiently for the device to boot into recovery mode.
2. You will see a dialog saying "Wipe Data Fail" – ignore this message and select the "Wipe Data" option.
3. Next, select "Wipe Cache Partition" (this is the top option in the menu).
4. Confirm the action and wait for the process to complete. You will see a notification saying "Wipe OK (Wipe Cache Successful)" when done.
5.  Finally, select "Reboot" to restart your device.

The phone will now restart and begin the initial setup process, just like a brand new device out of the box. All previous lock screen settings have been successfully removed.

Step 4: Unlock google account verification (Factory Reset Protection) Google Account

Our work is not done yet! Since we performed a forced factory reset, Google’s Factory Reset Protection (google account verification) will automatically activate. This means when you try to set up the phone, you will be asked to verify the Google account that was previously synced on this device. To Unlock this, we will use the RBSoft Mobile Tool.

Preparation for google account verification Unlock:

• Ensure your computer has a stable internet connection.
• Disable your antivirus software temporarily – some antivirus programs may flag RBSoft as malicious and block its operation.
• You will need to enter EDL mode again via the test point method (repeat Step 1 above to connect your Vivo Y91 in Qualcomm HS-USB QDLoader 9008 mode).

google account verification Unlock Steps with RBSoft:

1. Right-click on RBSoft Mobile Tool and select "Run as Administrator".
2. Enter the Username and Password provided in the "How to Use" notepad file that comes with the tool, then click "Login".
3. Select the "Manual Loader" menu, click "Browse", and locate the extracted Emmc Firehose file for Vivo Y91 (same file used in QFIL step). Click "Open".
4. Double-check that your Vivo Y91 is properly connected in EDL mode (Qualcomm HS-USB QDLoader 9008 visible in Device Manager) and your internet connection is stable.
5. Click the "Reset google account verification" button to start the Google account Unlock process.
6. 6. Wait for the process to complete. You will see log messages in the "Logs Window" – look for the "OK" status highlighted in green.
7. Once you see the success logs, the google account verification Unlock is complete.

Final Steps

1. Disconnect the USB cable from your phone.
2. Power on the Vivo Y91 and proceed through the initial setup steps. You will notice that the Google account verification step is now skipped, allowing you to set up the device with a new Google account or use it without one.

Conclusion

That concludes the complete tutorial on how to Unlock pattern lock, PIN, and google account verification Google account on the Vivo Y91. If this guide helped you solve your problem, please consider supporting us by sharing this article or liking our fan page. Thank you for visiting, and see you in the next tutorial!