ARB in Xiaomi devices: the complete guide to Anti Roll-Back

If you own a TV, smartphone or other Xiaomi device and you come across the term ARB (Anti Roll-Back), you've probably tried to update your firmware, unlock your bootloader, or install custom software. This security mechanism has been a headache for many enthusiasts, but it's still little known to ordinary users. What is ARB, why it blocks updates, and can you get around it? Let's get it out of the technical jungle.

In 2018, Xiaomi began implementing Anti Roll-Back in its devices, first in smartphones and later in Mi TV/Redmi TVs. The bottom line is simple: the system remembers the firmware version and does not allow you to “roll back” to the older version, even if you try to do it through official tools. On the one hand, this is protection against vulnerabilities (for example, if the old firmware had a critical flaw), on the other – headache if you accidentally upgraded to the “raw” version or want to return to a stable build.

In this article, we will discuss in detail:

What is ARB and why is it needed in Xiaomi?

ARB (Anti Roll-Back) is a hardware protection that blocks the installation of firmware older than the one already installed on the device. The mechanism works at the bootloader level and is independent of the operating system. Even if you completely reset the device or reflash it through the Fastboot, the ARB still works if the firmware version is lower than the current one.

Why did Xiaomi implement this system?

• 🔒 Security: Old firmware may contain vulnerabilities exploited by hackers. ARB Prevents the rollback to unsafe versions.
• 📉 Stability: Users often complain about bugs in new updates and try to revert to the previous version. Xiaomi thus forces them to stay on the current builds.
• 🛠️ Device support: The company saves resources by not supporting outdated versions of software for all models.

It is important to understand that ARB is not the same as locking a bootloader. The bootloader can be unlocked (for example, through the Mi Unlock Tool), but the ARB will remain active. Moreover, on some devices (for example, Mi TV 4S/5), it is not possible to unlock the bootloader at all without official permission from Xiaomi.

How to check if there is an ARB on your device

Not all Xiaomi devices are equipped with ARB. To find out if protection is activated on your device, follow the following steps:

1. Go to Fastboot mode: On your smartphone: turn off the device, then press Volume Down + Power. On your TV: Press Menu + Volume Down on the remote and plug in the power.

fastboot getvar anti

If the answer appears as anti: 5 (or another number), then ARB is active. If there is no answer, there is no protection.

You can also check the ARB version (if any) with the command:

fastboot getvar anti_version

The higher the number, the stronger the protection, anti_version: 3 This means that you will not be able to install the firmware with the version. ARB below 3.

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If the fastboot getvar anti command returns the error, try first entering fastboot oem device-info – on some devices, information about ARB is hidden there.

What Xiaomi devices have ARBs in

ARB didn’t appear on all Xiaomi devices, only those released after 2018. Below is a table with popular models and protection status:

Important: On Xiaomi TVs with ARB 4+, firmware rollback is almost impossible without an official tool from the manufacturer, this applies to models released after 2020 (for example, Mi TV Q2 or Redmi Smart TV X).

If your model is not in the table, check the ARB through Fastboot (instruction above). You can also search for information on forums such as 4PDA or XDA Developers, where enthusiasts collect databases on protection on different devices.

Can I bypass ARB on Xiaomi?

Technically, you can bypass ARBs, but there are risks involved, depending on the type of device and the version of protection:

• 📱 Smartphones: Use EDL-Emergency Download Mode and flash the device through the official Mi Flash tool with the right firmware. ARB (for example XDA).
• 📺 TVs: On some models (e.g. Mi) TV 4S) we can roll back through ADB, if ARB No higher than 3. ARB 4+ You will need an official firmware file with Xiaomi’s signature, which is almost impossible to obtain legally.

⚠️ Attention: Bypass ARB may lead to:

• Lose the warranty.
• "Break" of the device (complete inoperability).
• Blocking your Mi Account (if Xiaomi suspects a hack)

If you're not sure what you're doing, you should go to a service center or give up the idea of a rollback. There are often stories on forums where users, after a failed ARB bypass, get TVs that say "This device is corrupted" and have to buy new motherboards.

ARB vs Fastboot: What's the difference?

Many people confuse ARB with Fastboot or bootloader locking.

Put simply:

• Fastboot is a tool like a screwdriver, and it can either fix a device or break it.
• The bootloader lock is a lock on the door, and it can be opened with the official key (Mi Unlock).
• ARB is a pin in the wall that can't be removed, you can only work around.

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If both bootloader and ARB lock are active on your device, unlock the bootloader first, and then try to bypass Anti Roll-Back. Order is important!

Step-by-step: how to update the firmware without triggering ARB

If you want to upgrade your device without risking an ARB, follow this algorithm:

Download the official firmware from the Xiaomi website|Check the version. ARB fastboot|Make sure the new firmware is no older than the current one|Make a data backup|Update with Mi Flash or OTA-->

Let's take each step in more detail:

1. Download the correct firmware: Use only official files from the sites: Xiaomi Firmware Download (for smartphones). TV ROM (TV-set). ⚠️ Note: Firmware from third-party resources (for example, 4PDA) may be modified to contain viruses or incompatible versions ARB.
2. Check the version. ARB: How to do this, we told above (the team fastboot getvar) anti_version). Compare it to the version in the downloaded firmware. ARB lower than on the device - the installation is blocked.
3. Select firmware method: For smartphones: Through Mi Flash (recommended for clean installation). Through OTA (air update) is the safest way.

For TVs:

• Through USB-update (update.zip file at the root of the flash drive).
• Through ADB (power-user).

If you are upgrading a Xiaomi TV, note that on models with ARB 4+ (for example, Mi TV Q1) rollback to the previous version of the firmware will lead to locking the device, in which case only contacting the service center with official firmware will help.

Frequent Mistakes and How to Avoid Them

When you're working with ARB, you often make critical mistakes, and here are the most common ones:

• 🔄 Attempt to roll back on the old firmware: If on the device ARB 3+, You are trying to install a firmware with ARB 2, get the "Anti rollback check fail" error. Solution: Look for firmware with the same or higher version ARB.
• 🔌 Firmware Interrupt: If during the Fastboot update or EDL If you turn the device off from your PC, it can turn into a brick. Always use the original cable and power source.
• 📥 Use of unofficial firmware: Custom software (e.g. LineageOS) is often overlooked ARB, Check the compatibility on the forums before installing.

If you have an “Anti rollback check fail” error, try:

1. Reflash the device to the same version of the software (sometimes helps "rewrite").
2. Find firmware with higher ARB (for example, if you have anti:3, try firmware with anti:4).
3. Contact Xiaomi Service Center to reset your ARB (sometimes it helps if you have a check).

FAQ: Answers to popular questions