Warm Tips for Flashing Firmware on Vivo Y91C:

Before you begin flashing or updating the firmware on your Vivo Y91C, it’s important to follow a few essential steps to protect both your device and your data. Carefully reading these tips will help you avoid common mistakes and complete the process smoothly.

Important Note:

Due to system limitations starting from Android 8 and above, your Vivo Y91C — which runs on Android 8.1 or higher — cannot flash or downgrade to a firmware version lower than your current system version. Attempting to do so may result in installation failure or system issues.

To check your current software version, simply go to Settings > System Update on your Vivo Y91C. Always make sure that the firmware you’re flashing is the same or a newer version.

Before You Start – Backup Your Data & Check Battery:

We strongly recommend backing up all important data like contacts, photos, videos, messages, and app data before proceeding. Flashing your phone’s firmware may result in data loss, so keeping a backup prevents permanent loss. You can use Vivo Cloud, Google Drive, or transfer your files to your computer or an SD card.

Also, ensure that your Vivo Y91C has enough battery life — at least 30% charged — to prevent any interruption during the process. If the phone powers off while flashing, it could lead to system damage.

Step 1: Download the Correct Firmware for Vivo Y91C

• Visit the official Vivo website and navigate to the Support or Downloads section.

• Find the exact firmware version designed for the Vivo Y91C model.

• Download the firmware package directly to your phone or a computer.

⚠️ Important: Double-check that you’re downloading the correct firmware for the Vivo Y91C. Flashing the wrong version can cause serious issues, including system errors or the phone failing to boot.

Step 2: Move the Firmware Package to the Root Directory

• Once downloaded, move the firmware package (usually in .zip format) to the root directory of your Vivo Y91C’s internal storage or SD card.

• Do not unzip or extract the file. The package must remain exactly as downloaded.

Tip:
The root directory is the main area you see when you open File Manager or Google Files — it’s not inside any folder. When you open Internal Storage, the files you see right there are in the root directory. Place your firmware package here.

Step 3: Install the Firmware on Vivo Y91C

Based on your phone’s condition, follow the suitable method below:

If Your Vivo Y91C is Functioning Normally:

1. Go to Settings > System Update.

2. Tap the Settings icon in the top-right corner.

3. Select Local Upgrade.

4. Locate the firmware package you placed in the root directory.

5. Tap the file to start the installation.

Your Vivo Y91C will automatically verify the firmware package and begin the installation process. Your phone may restart several times — this is normal. Please be patient and avoid interrupting the process.

If Your Vivo Y91C is Not Booting or Stuck:

1. Power off your Vivo Y91C completely.

2. After the screen goes black, press and hold the Volume Up and Power buttons together until the phone enters FASTBOOT Mode.

3. Use the Volume Down button to scroll and select Recovery Mode.

4. Press the Power button to confirm.

5. Once in Recovery Mode, select Install software.

6. Choose Phone Memory or SD Card, depending on where you stored the firmware.

7. Locate the firmware package and tap Install.

Your Vivo Y91C will start installing the firmware. Do not press any buttons or turn off the phone while the installation is in progress. Once finished, your phone will reboot automatically with the updated system.

Additional Reminders for Vivo Y91C Users:

✅ Avoid powering off the phone or disconnecting it during the installation.
✅ Confirm that the firmware file is fully downloaded and not corrupted.
✅ After the update, you might need to restore your backup and reconfigure settings.

By following these steps carefully, you can successfully flash the firmware on your Vivo Y91C — whether you’re updating your system, fixing issues, or giving your phone a fresh start.

If you encounter any problems or feel unsure at any step, it’s always a good idea to reach out to Vivo Customer Support or visit the nearest Vivo service center for professional assistance.