The N2G47H 7.9.21 update for Xiaomi Mi A1 fixes issue of Slow Motion not working during taking video, Slow Fingerprint Unlocks speed and others. Also, the update includes September 2017 security patches to fix recent critical vulnerabilities. Below is the full change log of this update.

Changelog (N2G47H 7.9.21): The N2G47H 7.9.21update for the Mi A1 weighs in at around 1.3GB. If you have not received the new software update yet, just go to Settings > About Phone > Software updates. If update available, it will start downloading the latest update automatically. Experienced users can install the update manually by downloading the full firmware (fastboot ROM) on to PC. However, it requires unlocked bootloader on phone and ADB and Fasboot driver setup on the PC.

How to Install Stock Firmware (Fastboot ROM) on Mi A1 Manually

  1. Download N2G47H 7.9.21 with September, 2017 security patches for Mi A1 (codenamed tissot) [here].
  2. Now, follow this installation instruction. Note: For a successful installation, phone battery should be at least 50% charged. Also, this process will wipe your device completely, so back up all data before proceeding with the installation. (Source – MIUI)