I read about it, and does it only apply to freezes? Are there any benefits for doing this? Do files get erased?
iPhone 4S
Holding Lock and Home buttons will restart the iPhone, iPod touch or iPad. This is used when the device is frozen and you can't turn it off, and normally it's used only for this. This doesn't erase anything
You can also use those to buttons to take a screenshot of your screen, this is saved as a photo on you phone.
A2020 wrote:
You can also use those to buttons to take a screenshot of your screen, this is saved as a photo on you phone.
It should be noted that you don't take a screen shot by holding down those two buttons, as the OP asked about. You take a screen shot by tapping them at the same time.
You are yanking power away from the OS without allowing it to shutdown normally. It is a last resort measure. Just holding the top power button until asked to power off is the preferred way to remove power.
I am holding down both buttons but nothing happens. When I release them it takes a picture.
What does holding down the Home and Lock button do?
