Your iPhone was Accidentally blocked and only the apple symbol appears on your screen. Have you put the device in a recovery mode and the problem still occur?
I know you have been hearing that the only solution to this iPhone problem is to get your iPhone device into DFU mode, but have you taken time to enquire what it is and how to go about it?
DFU mode stands for Device Firmware Update mode, it allows you to connect the handset with iTunes without having to go through the iBoot boot loader and therefore does not load the original iOS version.
This method is used especially in those terminals in which it has become Jailbreak and has not gone well or want to return to a previous version of iOS.
Before you begin, you should know that once you put your iPhone in DFU mode you will lose all information, applications, pictures, etc, that you have not previously synced with iTunes.
So, it is important that you go creating backup your computer regularly to avoid losing data.
How to get an iphone into dfu mode
==> Open iTunes on your computer and connect the terminal via the USB cable
==> Then, turn off the device as usual, holding the power button until the display shows the red bar ‘Shut Down’.
If you can not turn off your iPhone in this way, tap the home button and the power button at the same time and not let go until it turns off.
==> When you have turned off the terminal, you must simultaneously press the Home button and the Power button for 10 seconds exactly.
It is very important to count the seconds for the DFU mode is activated properly. If necessary use a stopwatch. Normally, after 10 seconds the apple off the screen by leaving it in black, this is a little trick to calculate the latter.
==> After 10 seconds, release the on / off but no boot. You must hold down the home button until iTunes recognizes the device in Restore Mode, usually it takes another 10 seconds.
==> When the window appears so restoration, press ‘OK’ and go! You already have your iPhone in DFU mode (screen should be black, if it goes any logo you are in this mode) and you can restore from iTunes.