...As long as the volume up key + home key + power key does not work

As long as the volume up key + home key + Power key does not press enter simultaneously?

aside after connect charger with phone and the volume up key + home key + Power key

press enter simultaneously a msg appear " A custom OS can cause critical problem in phone and installed applications.

if you want to download a custom OS press the volume up key.

otherwise, press the volume down key to cancel.

i am trying to press volume up key but nothing happen...