Need to downgrade your Redmi Note 6 Pro back to MIUI 9? Below you can download MIUI 9 ROM v184.108.40.206 and v220.127.116.11. While the earlier is available as Fastboot package, the later is available in both Fastboot and Recovery ROM packages.
Xiaomi Redmi Note 6 Pro has codename Tulip. The device is an iteration of Redmi Note 6 Pro codename Whyred. Similarly, the MIUI running on it also brings Anti-rollback Protection as one of its security features.
Unlike the 5 Pro (Whyred), the 6 Pro is rolled out with ARB 4. The Anti-Rollback Protection index is crucial to determine whether you can downgrade your phone or not. Upgrading is not affected with the ARB protection, of course.
Some builds of MIUI 10 for Redmi Note 6 Pro still have ARB 4. It means you can easily downgrade your phone from MIUI 10 to MIUI 9. Nevertheless, it is always the best practice to check for ARB Index before attempting to downgrade your phone.
Download MIUI 9 ROM
The default release of Redmi Note 6 Pro was MIUI 9. Below is the fastboot file of MIUI 9 v18.104.22.168 which is the initial build comes shipped with every new Redmi Note 6 Pro device. However, this may change in the future device.
The ROM is based on Android 8.1 Oreo.
Download MIUI v22.214.171.124 Fastboot ROM
This default build of MIUI has no Recovery ROM. It means you have to always use Mi Flash to install the ROM through Fastboot method.
Download MIUI v126.96.36.199 Fastboot ROM
Useful article: How to flash MIUI Fastboot ROM.
Download MIUI v188.8.131.52 Recovery ROM
Useful article: How to flash MIUI Recovery ROM.
All MIUI ROM files available above are original, unaltered, and unmodified. All files are available for download via direct hot link. You may use your favorite Download Manager software to accelerate the process.
Credits to MIUI.