Xiaomi rolled out MIUI10 Global Beta for some Xiaomi devices. When users installed the update on their Xiaomi Redmi Note 5 Pro, they unknownly flashing a build with anti-rollback protection enabled. Users who didn’t like MIUI 10 Global Beta found a big surprise when they tried to re-install the latest MIUI 9 Global Stable ROM: their phones were bricked!|
This wasn’t the kind of brick that you could fix by restoring a TWRP backup, flashing a new ROM, or using MiFlash to restore to a factory image. This is a hard, unrecoverable brick that requires the use of EDL mode to fix. But EDL mode isn’t accessible unless you have an authorized account, so many users were left with no way to fix their phone except sending it in to an authorized service center or paying to use someone’s account with EDL access. In this article, we’re going to explain everything you need to know about Xiaomi’s new anti-rollback protection so you can avoid bricking your new phone.
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Why does Xiaomi require long bootloader unlock wait times, EDL authorization, and Anti-Rollback Protection?
Xiaomi is the most popular smartphone brand in Asia. thanks to their wide selection of budget and mid-range devices. Like Huawei, Xiaomi also sells a ton of smartphones in their home market of China. Many of these devices are never sold outside of China, but that doesn’t stop people from importing them. Unofficial retailers for Xiaomi products have sprung up on Aliexpress, Gearbest, and other plenty of other websites, allowing anyone from outside China to buy the latest Xiaomi products. This has posed a challenge for the company as the software they ship on their Chinese devices, called “MIUI China,” does not contain Google Play Services, the Google Play Store, or languages other than English or Mandarin. Thus, anyone who imports a Xiaomi device from China shouldn’t be getting Google apps and services outside of the box.However, third-party retailers figured out a way around this so they could convince customers they were selling Xiaomi devices with an “official” MIUI Global ROM. The retailers would buy Xiaomi devices in bulk, unlock the bootloader, change the software themselves or flash a custom ROM like Xiaomi.eu (unofficial ROMs based on MIUI China but with more languages and features), and then sell the device. Most consumers would have no way of knowing they’re running unofficial/modified software, and would instead blame Xiaomi for a lack of updates or bugs they encounter. Even worse, some retailers would intentionally bundle malware or adware so they could make a bit of extra money. Xiaomi’s reputation was actively being harmed by this practice as tech reviewers and consumers were caught up in the schemes of these unofficial retailers, and so they needed to come up with a way to stop shady retailers from selling modified devices in bulk.One solution is to completely block bootloader unlocking, which is a drastic move that Huawei recently took.
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Seeing their brand’s success among enthusiasts, Xiaomi hasn’t moved to block bootloader unlocking just yet. Instead, they’ve implemented a few roadblocks to safeguard users against the actions of malicious third-party retailers.
Bootloader Unlock Wait Times
First, Xiaomi implemented a waiting period for bootloader unlocking. Xiaomi devices, save for the Xiaomi Mi A1, Xiaomi Mi A2, and Xiaomi Mi A2 Lite which run stock Android under the Android One program, require the use of Xiaomi’s proprietary Mi Unlock tool to unlock the bootloader. After sending your request to unlock the bootloader, Mi Unlock forces you to wait before it validates your request and unlocks the bootloader. The waiting time used to be 3 days before increasing to 15 days in early 2018, and recently, the waiting time has increased to 30 or as high as 60 days in some instances. (Xiaomi’s new sub-brand, Poco, lowered the waiting time to 3 days after receiving feedback from the MI community), Adding a wait time to the bootloader unlock process was effective in slowing down the operations of third-party retailers.
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Next, the company began to lock down EDL mode on their devices. EDL stands for Emergency Download Mode, and it’s an alternative boot-mode on all Qualcomm devices that’s commonly used to unbrick your device. In order to make use EDL mode, you need to find what’s called a “programmer” that has been authorized by the OEM (Xiaomi) for use on your device. EDL mode is very powerful and very low-level, and it’s routinely used by service centers to repair devices. However, EDL mode was also commonly used to flash both official and modified MIUI Global ROMs on Chinese Xiaomi devices without unlocking the bootloader. In essence, EDL mode became another way that third-party retailers could bypass Xiaomi. Xiaomi doesn’t want consumers buying Chinese versions of their hardware with Global ROMs installed, so they did two things: Made it impossible to boot a Global ROM if the device isn’t a Global version (with the warning message “This MIUI can’t be installed on this device”), and made it so EDL mode can’t be used unless you have an authorized Mi account.
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Finally, they implemented anti-rollback protection in the latest versions of MIUI for the latest Xiaomi devices. You may have heard of anti-rollback protection before. Google added support for the feature in Android 8.0 Oreo and made it mandatory for devices launching with Android Pie. Google’s anti-rollback protection is a feature of Android Verified Boot 2.0 (also known as Verified Boot) and it prevents the device from booting if it detects that the device has been downgraded to an older, unapproved software build. Anti-rollback protection is necessary to prevent attackers from loading older software on a device that’s susceptible to an exploit. The biggest difference between Google and Xiaomi’s implementation is that Google’s anti-rollback protection is disabled if you unlock the bootloader while Xiaomi’s can’t be disabled. Once you install a build with anti-rollback protection enabled on a Xiaomi device, there’s no going back. Here's a device list you can check.
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What do I do if I bricked my phone?
If you bricked your phone by triggering anti-rollback protection, you have very few options. Send your device to Xiaomi authorized service center for repair. The service centers have access to restore your device via EDL mode. As you can see, bricking your phone by triggering anti-rollback protection is no joke. You really need to be careful before you flash any older MIUI version.
A few weeks ago, an Administrator of the official MIUI forums announced that this behavior was intentional. From the forum post:
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Frequently Asked Questions (FAQs)
*What do I avoid if I don’t want to brick my device?
Don’t flash a MIUI version with a rollback index less than your device’s current rollback index. See above for instructions. Don’t flash an official MIUI Global ROM on Chinese Xiaomi hardware with a locked bootloader.
*Can I still install custom AOSP ROMs, kernels, Magisk, Xposed, ARISE, and other mods?
*Can I still switch between MIUI Global Stable, MIUI Global Developer, MIUI China Stable, and MIUI China Developer?
Yes, but you need to compare the rollback index before you install an older MIUI version..
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Be safe with your devices and enjoy. If you have any further questions or concerns please comments below. Thanks
Source: MI community. XDA