http://webtrickz.com/how-to-downgrade-mi-3-to-stable-miui-rom/
Want to downgrade your Mi 3 from Developer ROM to Stable ROM? MIUI Developer ROMs are officially provided by MIUI to let interested users test the beta version of upcoming MIUI OS, which helps them resolve any reported bugs and obtain user feedback prior to the final release. The Developer ROMs are updated every week with bug fixes and new features as compared to Stable ROMs that don’t have a regular update frequency. Perhaps, if you’veinstalled a developer ROM on your Xiaomi smartphone (Mi 3/ Mi 4) and are encountering serious bugs and app crashes, then you might want to revert back to Stable ROM.
In the below guide, we’ve covered the easiest and safest way to downgrade Mi 3 MIUI ROM to Stable version by flashing the Full ROM pack. A Full ROM includes all the apps and services in a ROM, even those haven’t changed in an update. You can also fix some problems in your device by flashing the full ROM pack. This method neither requires using the Mi Flash tool (involves booting into fastboot mode) nor using a custom recovery like CWM. You can easily perform the entire process without requiring a computer and technical knowledge.
Guide to Install Stable MIUI 5 ROM (v23) on Xiaomi Mi 3 -
Note: In this process, the user installed applications and media such as files, photos, music, etc. wont be deleted. Only the user data will be deleted which includes device settings, added accounts, and the settings & data for installed apps. You can take a backup if required.
1. Download Stable Full ROM pack for Mi 3 (WCDMA India) – Version: KXDMIBF23.0 (V5)
2. Copy the file to the root directory of the phone.
>> Rename the file miui_MI3WGlobal_KXDMIBF23.0_69adb845f8_4.4.zip to update.zip.
3. Boot into recovery mode – To do so, either (go to Tools > Updater > press Menu key and select ‘Reboot to Recovery mode’) or Power off your Mi3 and turn it on again by pressing Volume Up + Power button simultaneously and hold them until Mi-Recovery mode appears.
4. In recovery mode, use volume keys to navigate and power key to confirm. Choose English, then select ‘Wipe & Reset’ from Main menu. Navigate to ‘Wipe User Data’ and select Yes.Note: When wiping data is at 98%, wait for a while as it takes few minutes to complete.
5. Now go back to main menu, and select ‘Install update.zip to System One’. Select Yes to confirm and the update will begin installing.
6. When Update is installed, go back and select Reboot. Select the option ‘Reboot to System One (latest)’. Be patient after reboot as Mi 3 will take around 5 minutes to boot up.
That’s it! Your Mi 3 should now be running the latest MIUI v5 Stable ROM.
Hope you found this tutorial helpful. 
P.S. We’ve tried this procedure on Mi 3W (Indian version) running MIUI v6 Developer ROM.
