1. Generally, the official Recovery will have the option of applying sdcard: (sweep ROM upgrade package)
Android system recovery <3e>：
rebott system now: Restart the system
apply sdcard:: Brush ROM package
wipe data/factory reset: Restore factory value
wipe cache partition: Clear partition cache
apply sdcard: is an option to refresh the ROM upgrade package. If you want to flash the machine (it is like reinstalling the system on your computer), you can change the name of the ROM package downloaded online, and then select the apply sdcard: option through the volume increase or decrease key to flash the downloaded ROM package (equivalent to reinstalling a system).
2. Flash the machine
When you press (house key + "Volume + Key" and boot key) when you turn on your Android phone, you will enter the Recovery mode of the Android system.apply sdcard:It appears here, unplug the battery and exit this interface. If you see the word Android system recovery <3e> in the first post, it means that your Recovery is the official Recovery. If you flash the machine, it is best to flash the third-party Recovery first, as the function will be more powerful and the flash will be more convenient.