I think I nearly reset my phone accidentally?

[Sammy]

So I turn my phone off every night before I go to sleep and turn it back on in the mornings. But this morning, I think I accidentally pressed a wrong combination of buttons and activated some sort of process?
I went to press the standby button (most right of the four) but I think my finger also depressed the ringer volume down button on the side of the phone.

My phone was turned off, but after this it went to this white screen, which looked like the same one as when we had to do the ROM update. Then later I pressed menu, because it said to abort press menu.

Then it started loading up like normal.

Does anybody know of any combinations of buttons that does this sort of thing so I can avoid it in future?

 

[vido.ardes]

If you hold down the back button while switchng it on, it will enter the bootloader (the white screen)

 

[Sammy]

What would one normally do in the bootloader?

 

[JayCee]

What would one normally do in the bootloader?

Reset it to its out of box condition.