Realme 3i RMX1821 Flash File | Stock Firmware Guide

Here we will guide you on how to flash the firmware file on Realme 3 Pro (Model No: RMX1851). The guide is simple and easy to follow. You can watch our complete video guide. Realme 3i (model: RMX1821) smartphone is an entry-level budget smartphone that comes with 3/4 GB of RAM and Android 9.0 Pie. It’s powered by quad-core MediaTek MT6771 Helio P60 SoC, 32/64GB of internal storage which is expandable. The handset offers a 6.2-inch display, 4230 mAh battery, a 13MP + 2MP rear, and a 13 MP selfie camera. Here in this guide, we will share with you all the flash files and instructions to install the Realme 3i firmware flash file].

Due to Android’s open-source nature and easily customizable functionalities, users or developers can tweak or use mods on Android devices. It will lead the device system quite laggy or buggy as well. If in case, you’re facing performance issues with the software, you should reinstall the Stock Firmware. By flashing the Stock ROM again on your Realme 3i smartphone, you will get back on track easily.

Additionally, most of the advanced users always perform flashing, taking backups, restores, customizations, Custom ROM flashing, flashing Root, etc. In these cases, you may find that the third-party custom firmware doesn’t work smoothly or doesn’t offer stability like a Stock Firmware. Therefore, you can feel that get back to the Stock ROM will be useful for that moment. If you really facing these kinds of issues and wants to go back to Stock ROM, follow the full detailed guide and requirements.

How to Install Stock ROM on Realme 3i RMX1821 [Firmware Flash File]

Realme 3i Specifications: Overview

The Realme 3i is a budget device offers a good value for money specifications. The handset comes with a 6.2-inches HD+ display with a resolution of 1520×720 pixels. It is powered by an octa-core MediaTek Helio P60 SoC coupled with ARM Mali-G72 GPU. The device packs with 3GB/4GB of RAM and 32GB/64GB of internal storage option. While the storage can be expandable up to 256GB via a MicroSD card. It runs on ColorOS 6.0 on the top of Android 9.0 Pie out-of-the-box.

The smartphone sports a dual rear camera setup of 13MP+2MP AI sensors with PDAF, f/1.8 aperture lens, Nightscape, Hybrid HDR, Chroma Boost, Portrait mode, and more along with an LED flash. While the front features a 13MP AI selfie camera with HDR, AI Beautification mode, AI Facial Unlock. While the device camera features 720P and 1080P video recording @30fps and 720P slow-motion @90fps.

It packs a decent 4,230 mAh non-removable battery. The device has a dual Nano-SIM slot and a dedicated MicroSD card slot. It features 4G Dual VoLTE, Wi-Fi 802.11b/g/n, Bluetooth 4.2, GPS, A-GPS, GLONASS, Micro-USB port, a 3.5mm headphone jack, and more. In terms of the sensors, it includes E-Compass, Ambient Light, Proximity, Gravity, Accelerometer, and a Fingerprint Sensor.

Stock Firmware and its Advantage

The smartphone OEMs don’t provide that much of customizations or functionalities to the device by default. But it’s the most stable ROM according to the device model and Android version.

While most of the third-party firmware comes with system bugs and stability issues. In this case, you may find battery issues, camera issues, network issues, basic features missing, lags, heating, slow down in performance, and more. But whenever you move to the Stock ROM, you can fix these issues easily. Here we have mentioned some of the Stock ROM advantages below:

  • Flash Stock To Unbrick your Realme 3i
  • Fix the device boot loop issue on Realme 3i
  • Upgrade and Downgrade your phone software version
  • Flash Stock ROM to unroot the device
  • Fix Bugs on your Realme 3i
  • Fix lag or stutter on Realme 3i
  • Increase software performance, battery draining issue, OTA update issue
  • Revert back to Stock ROM will gain phone warranty (if applicable)

Firmware Details:

  • Device Supported: Realme 3i (RMX1821)
  • Tool Supported: Smartphone Flash Tool
  • Processor: MediaTek MT6771 Helio P60 SoC
  • Android OS: 9.0 Pie
  • File: Software Update
  • Gapps: Included

Check for OTA Updates Manually

Your device will itself detect and grab the OTA when it becomes available. You will get a notification to install it. If you don’t get the OTA automatically, then manually check for the update. Follow these simple steps mentioned below.

  • Go to the device Settings > System menu > System Update > Tap on Check for Update option.
  • If the OTA update appears then tap on Download and install to begin the installation process.
  • It may take a few minutes and then reboot your device.
  • Now, your handset will boot into a new system.

Now, you have to download the Stock Firmware file for Realme 3i (RMX1821) from below.

Download Firmware

Steps to flash the firmware file on Realme 3i 

Now, follow the full step-by-step installation process to easily flash the Stock Firmware on your Realme 3i device. But before heading over to the installation process, let’s take a look at the requirements.


  • ROM file supported: Realme 3i only. Don’t use it on other devices.
  • Charge the device battery up to 60% at least for a smoother process.
  • You will require a Windows PC/Laptop and a USB cable to connect your device with the PC.
  • Download and install USB drivers on your computer.
  • You need to download the SP Flash Tool and install it on your PC.


We’re at GetDroidTips will not be responsible for any kind of error/issue that occurs to your device while/after installing this firmware or following this guide. Proceed at your own risk.

Instructions to install:

Now, let’s go to the installation steps. Here we have provided the installation method in both writing and video guide.

Method 1: Instructions to Install via Recovery:

First, you can try the official method to install the OTA stock ROM update via Realme device recovery.

Method 2: Instructions to Install via SP Flash Tool

Now, without wasting any more time, let’s jump into the firmware installation steps below:

  1. Make sure you follow and download all the required files and flash tools on your PC.
  2. Open the flash tool exe file to open the SP Flash Tool User InterfaceSP Flash Tool Folder
  3. Once your load the SP Flash tool UI, Tap on Download option
    SP Flash Tool Screen
  4. In the download tab, you have to load both the download agent and the scatter text file in the scatter-loading section.
  5. You will find the scatter text file inside the ROM package for most cases, if not, you can create a scatter text file on your own.
  6. Once you load the file, click the Download buttonSP Flash Tool Download Button
  7. To start the upgrade process of stock ROM on your Realme 3i, you need to turn off your device and hold the Volume Down and Volume Up key together and Connect your Phone to PC/Laptop using USB Cable (Keep the Volume Down and Volume Up button until your computer detects the phone.)
  8. When the phone connects, your device will start upgrading the stock firmware
  9. You need to wait for a few minutes to complete the upgrade process.
  10. Once the flashing process completes, you will find a green button which means a successful upgrade. sp green ring
  11. That’s it! You can reboot your Realme 3i

Follow our full-depth video guide below:

Video Guide to Install Stock ROM via SP Flash Tool

We hope that you have successfully installed the Stock Firmware on your Realme handset model Realme 3i (RMX1821). For any queries, you can write them down in the comments below.

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