You can long press the “工程模式” icon to make it disappear automatically. 
Warmly Tips: If you enter Factory test interface unconsciously, please don`t perform any operations. Vivo will not be responsible for any damage caused or changes that happen during or after the operations on this interface.

Yeah. V9 Pro supports DLNA. You can go to Settings>More settings>DLNA to turn it on.

Please be assured that it won`t cause any damages on your phone. However, it will clear the system data such as all third-party apps, contacts on your phone. We suggest you back up your important data before performing it.

Yeah. It is equipped with the Protective Case. You can find it in the phone box.

In order to make sure the system run smoothly and stably, some RAM is reserved for the system and it is not recorded in Running interface. That is why the total amount of the RAM the apps use is less than the Used RAM. Please don`t worry, you can be assured to use your phone.

V9 Pro does not support Hi-Fi. However, it supports DeepField Audio. You can turn it on in i Music.

V9 Pro supports Video calling for Jio currently.

We are sorry V9 Pro does not support to record 4k videos.

Yeah. V9 Pro supports Smart Mirroring(Wi-Fi Display). You can go to Settings>Smart Mirroring(Wi-Fi Display) to turn it on.

Yeah. It supports Dual Wi-Fi.