Download full firmware on Xiaomi Redmi S2: all the risks and consequences

Xiaomi Redmi S2 (codename ysl) is a budget smartphone of 2018 that is still used by many users. Over time, its performance declines and official MIUI updates stop coming out. In such cases, owners often consider installing full firmware — whether it is a stock version from Xiaomi or custom (for example, LineageOS). But what happens if you just download and try to flash the device? Does it get faster, turn into a brick, or other problems arise?

In this article, we will discuss in detail:

• 🔍 How full firmware is different from OTA-Update and why installing it is more risky.
• ⚠️ Major Mistakes That Lead to Redmi Inoperability S2 post-fix.
• 🛠️ How to Prepare to Minimize Risks (Actions List).
• 🔄 Can you go back if something goes wrong.

It's important to understand that the Redmi S2 is a device with a Snapdragon 625 processor and a closed bootloader by default, which puts restrictions on how you manipulate the firmware, and if you've never done that, think three times before you do it.

1. Full Firmware vs OTA: What's the Difference and Why It Matters

Many users confuse full ROM and regular over-the-air update (OTA) with the difference:

• 📲 OTA-An update is a patch that adds changes to an existing system, weighs little (usually 100-500 MB) and installs automatically, without the risk of losing data.
• 💾 Full firmware is a complete system image (1.5-2.5 GB) that erases all partitions of the device and rewrites them from scratch, and it is needed for radical changes: changing the region, recovering from a failure or installing custom firmware.

On the Redmi S2, full firmware can be of two types:

• 🔹 Stock (official) – from Xiaomi, for recovery through the Mi Flash Tool.
• 🔹 Custom – for example, LineageOS or Pixel Experience, requiring an unlocked bootloader.

The main danger: if you download firmware not for your model (for example, for Redmi Note 5 instead of Redmi S2) or choose the version incorrectly (Global vs China), the device will not boot or lose network, camera and other functions.

⚠️ Attention: On Redmi S2 You can not install firmware for devices on Snapdragon 636/660 (For example, Redmi Note 5 Even if they are visually similar, the iron is different and the firmware won't work.

2 Risks: What could go wrong with the Redmi S2 firmware

The firmware is always a lottery, and even if you do everything according to the instructions, you're going to run into problems.

The worst scenario is a hard brick, where the device doesn't respond to any buttons and isn't detected by the computer. On the Redmi S2, this happens if:

• 🔌 Interrupt the firmware in fastboot at the boot or system recording stage.
• 🔄 Try to get a custom recovery (TWRP) loader-free.
• 📱 Install firmware with incompatible bootloader (for example, from Redmi 6 Pro).

Recovery in such cases requires EDL-The Emergency Download Mode and the official Mi Flash Pro tool, which only works with authorized Xiaomi accounts.

Preparation for firmware: checklist of mandatory actions

If you still decide to firmware, be sure to follow these steps:

Make a backup copy of the data (photos, contacts, SMS)|Check the device model in Settings → The phone.|Download the firmware only for Xiaomi Redmi S2 (ysl)|Install Qualcomm drivers and ADB PC-only|Charge your phone at least 60%|Unlock the bootloader (for custom firmware)-->

Pay special attention to the firmware versions. For the Redmi S2, the official firmware is:

• 🌍 Global (World version, supports Google services).
• 🇨🇳 China (without Google, but with additional features) MIUI).
• 🇪🇺 EEA (European, with GDPR-restraint).

Download the firmware only from official sources:

• 🔗 Official website MIUI (Choose Redmi. S2 → ysl).
• 🔗 XDA Developers (for custom firmware).

Do not use files from torrents or questionable file sharing sites – they may contain viruses or be modified (for example, with malware preinstalled).

certutil -hashfile name file.zip MD5

Compare the hash you get with the official one on Xiaomi's website, and if they don't match, the file is corrupted or tampered with.

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Step-by-step: how to flash Redmi S2 without risks

Consider two scenarios: installing the official firmware through the Mi Flash Tool and custom through TWRP.

Method 1: Official firmware (Mi Flash Tool)

1. Unlock the bootloader (if not unlocked). To do this: Link the Mi Account to the device in Settings → Additional → For developers → Link the Mi Account. Connect the phone to the PC, go to fastboot (clamp the Volume down + Power) and execute the command: fastboot oem unlock

Download the firmware.

.tgz

.zip

non-Cyrillic

Install the Mi Flash Tool

clean all

clean all and lock

Connect your phone in fastboot mode

Refresh

Flash

Method 2: Castom firmware (TWRP + ADB)

1. Install TWRP via fastboot: fastboot flash recovery twrp.img fastboot boot twrp.img
2. Backup in TWRP (Boot, System, Data) sections.
3. Sweep through Install to TWRP (select the.zip file).
4. Clear the cache (Wipe → Dalvik / ART Cache).

After the firmware, the first turn on can take 5-15 minutes - do not interrupt the process!

⚠️ Note: If you have a customized ROM The phone does not load, but TWRP You get a dm-verity error, you need to turn off signature verification. TWRP file Disable_Dm-Verity_ForceEncrypt.zip (download XDA).

5.What to do if after the firmware Redmi S2 does not turn on

If the device does not respond to the power button or is stuck on the Mi logo, follow the algorithm:

1. Try going to fastboot: Press Volume Down + Power for 10 seconds. If the device is defined as fastboot, run the firmware again.
2. Check it out. EDL-Mode (if fastboot doesn't work): Connect the phone turned off to the PC by clamping Volume up + Volume down. If Qualcomm appears in Device Manager HS-USB QDLoader 9008 – can be flashed through Mi Flash Pro.
3. Restore. IMEI (If there is no network: Download the utility QCN Rebuilder and original QCN-file S2. Restore. IMEI via the engineering menu (#4636## → Information).

If nothing works, and the phone is not defined in fastboot or EDL, it's a hardware brick.

• 🔥 Short circuit on the board (for example, due to a faulty USB-port).
• 🔋 Damage to flash memory (eMMC) when the firmware is incorrect.

In such cases, only the replacement of the motherboard or the use of equipment for the service remains. ISP-Programming (direct access to memory through test points).

💡

If the Redmi S2 does not respond to buttons and is not detected by a PC, do not try to disassemble it yourself.Modern Xiaomi smartphones have autopsy protection, and improper actions can lead to final failure.

6. How to avoid data loss when firmware

Many users lose photos, contacts and messages after firmware because they don't backup. There are several ways to save data on the Redmi S2:

• ☁️ Cloud Backup: Upload photos to Google Photos or Mi Cloud. Sync your contacts with your Google account (Settings) → Accounts. → Google → Synchronization).
• 💾 Local backup: Use Mi Mover (the built-in Xiaomi app) to backup on your PC. DCIM, Downloads and WhatsApp manually via MTP.
• 🔧 Backup through TWRP (If installed: Save Data, System and Boot partition images on SD-map.

If you are installing custom firmware, consider:

• 🔐 Some of them ROM (For example, LineageOS requires formatting the Data partition in F2FS or ext4, That erases all user files.
• 📱 Applications linked to Mi Account (such as Mi Home or Mi Fit) may require re-authorization.

After you've installed the firmware, don't forget to turn off the factory protection (FRP) if you're selling your phone.

1. Go to Settings → Accounts → Mi Account.
2. Delete the linked account.
3. Perform reset to factory settings.

7.Myths and truths about the Redmi S2 firmware

There's a lot of conflicting information on the Internet about Xiaomi's firmware.

Another common fear is, "When you run the firmware, the phone will become less secure."

• 🔒 Xiaomi’s official firmware is being tested for vulnerabilities.
• 🛡️ Castomy ROM (LineageOS, for example, is often updated more frequently than stockware, but requires manual permission control.

The bottom line: firmware won’t make your Redmi S2 “hacked” or vulnerable if you follow proven instructions and download files from trusted sources.

FAQ: Frequent questions about the firmware Xiaomi Redmi S2