Here’s a short guide on how to reset engineering mode settings back to defaults on your Xiaomi Redmi Note 4 device. This also could be helpful when changes in engineering mode settings aren’t saving.
First thing you’ll need to do is to download and install ES Explorer or Root Explorer on your phone.
Next enter the phone root memory using the downloaded file explorer (root access is required) and go to the /data/nvram/APCFG/ folder (on some other ROMs it could be /nvdata/APCFG/APRDCL).
Open the “APRDCL” folder. Copy and backup this folder to the SD-card, your PC or any other device. It’s recommended to do these steps in “Airplane mode”, or this could lead to IMEI loss.
Next we delete the “APRDCL” folder and then restart our phone.
Open the engineering mode menu after phone restarts. All settings should be changed back to defaults. The deleted folder will be restored after restart.
Please note that you’re doing everything at your own risk, and we’re not responsible for any damage done to your device.