On July 12th, MIUI released a notice on the introduction of anti-rollback mechanism for Redmi Note 5 in the community. In order to maintain system stability and ensure the security of the device, we recently introduced an anti-rollback mechanism , MIUI. Versions 8.7.6 and above will not be able to downgrade the old version of the development or stable version.
MIUI also said that if you have previously updated your phone to version 8.7.6 and above or stable version V9.5.22 and above, please do not try to downgrade and brush back the old version, which may cause the phone to brick.
If you have upgraded to 8.7.6 or V9.5.22 and above, and brush back the old version, please contact customer service or go to the Xiaomi authorized service outlet to contact the staff to brush.
Previously, Google built a security feature called Rollback Protection in Android 8.0, which prevented the device from rolling back to the old firmware. Google did this for security reasons. The reason is that the security issues of the old version of the firmware can not be ignored.