Update 2 (07/15/2020 @ 05:32 AM ET): Xiaomi has rolled out a new bugfix for the Mi A3.

Update 1 (07/14/2020 @ 02:05 AM ET): Xiaomi has released a statement on the Mi A3's recent update issue. Scroll to the bottom for more information. The article as published on July 13, 2020, is preserved below.

Unlike the majority of smartphones on Xiaomi's portfolio, the Xiaomi Mi A3 runs a close-to-stock version of Android, thanks to its Android One branding. The Google-flavored Android UX also ensures that the device is eligible to get 3 years of monthly security updates. Matter of fact, Xiaomi has pushed a new security update for the global variant of the Mi A3 earlier today that does bring in the July 2020 Android security patches. But there’s a major problem: The latest update (V11.0.3.0.QFQMXTC) reportedly breaks the dual-SIM functionality of the phone, introduces a carrier-specific logo in the boot animation out of the blue, and commits a bunch of unexpected changes.

Xiaomi Mi A3 XDA Forums

Why does this happen?

As it turns out, today's update carries an entirely different identifier (QFQMXTC) than the global firmware (QFQMIXM). The "MXTC" tag is actually meant for Mexican telecom operator Telcel - the name which is visible in the altered boot animation.

Although the Mi A3 is an Android One phone, Xiaomi maintains a couple of regional firmware channels for this device. Apart from the global and European software builds that you can find on respective unlocked units of the Mi A3, there exist some variants of the phone sold through carriers that run carrier-customized firmware packages. Those builds often come with pre-installed network configurations, brandings, and apps corresponding to the particular carrier, just like the one rolled out a while ago.

Only this time, Xiaomi somehow mixed up the targets. Telcel's firmware basically disables the second SIM slot of the global (as well as Indian) Mi A3 models, virtually making it a single-SIM phone. It also comes with a handful of carrier "bloatware" apps.

What can be done about it?

If you've already installed the update, there is no easy way to revert back. Given that the bootloader of your Mi A3 is unlocked, then only you can manually flash the June 2020 global firmware (software version V11.0.16.0.QFQMIXM) on your phone using Mi Flash and regain the dual-SIM functionality.

There is now a post on the Mi Community, suggesting users not to install the rogue update. The OTA in question is about 1.40GB in size, which is much larger than typical security updates. Users are thus advised to take a look at the update size and skip it for the time being. This is a crucial bug that needs to be fixed by Xiaomi as soon as possible.

Source: XDA Forums (1, 2), Mi Community

Thanks to Mi Community member BOTROBOTMOD and Twitter user Kaushik Raman for the screenshots!


Update 1: Xiaomi's statement on the Mi A3's recent update issue

Xiaomi has released a statement on the Mi A3's recent update issue:

We are aware of the software update issue on a few Mi A3 devices. On further investigation, we have identified it to be a technical issue due to which a software update not meant for Indian users, was shared inadvertently. This issue has been fixed already from our side and our technical teams are working on a recovery solution that will be rolled out soon.

We will update the article as soon as the fix is made available for users.


Update 2: Mi A3 receives a new bugfix build from Xiaomi

Xiaomi has started rolling out a new firmware for the global variant of the Mi A3 to address the dual-SIM issue. Whether you're on build V11.0.3.0.QFQMXTC (i.e. the Telcel firmware) or V11.0.16.0.QFQMIXM (the June 2020 global firmware), you should be get the bugfix build with the version number V11.0.17.0.QFQMIXM. The size of the OTA package is 1.33GB and it carries June 2020 security patches.