[gTen]

I guess then there is nothing you can do other then:

1) Try pressing the camera button really hard and hope it works after X attempts of trying to enter bootloader (you never know when a press from soem random direction somehow makes it work once or soemthing)

2) Take apart your phone and fix/simulate the camera button press (Since buttons work pretty simple switch mechanics, but I wouldn't do this unless you have at least basic understanding of circuitry)

3) Take it in for repairs