Jailbroken iPhone 4 stuck at apple logo after installing Ultrasn0w

[raksrules]

I have an Iphone 4 with iOS 5 and baseband 1.59.00
I had jailbroken this iPhone few days back and today i tried installing Ultrasn0w on it. The process went fine and at the end it gave me a large button for "Reboot iPhone"
I tapped that and now my iPhone 4 is stuck at the white apple logo.
Now i know that it is tethered Jailbreak.
So i tried to keep the top button pressed to turn off the phone and it does not get turned off.

Now my best guess is to boot tethered and get it back in working condition...right ??
If yes then how do i put it into DFU mode and do a "JUST BOOT" so that it starts working again, given the condition that it is not shutting itself down when i keep the top button pressed ??

[R.Mortera]

I have an Iphone 4 with iOS 5 and baseband 1.59.00
I had jailbroken this iPhone few days back and today i tried installing Ultrasn0w on it. The process went fine and at the end it gave me a large button for "Reboot iPhone"
I tapped that and now my iPhone 4 is stuck at the white apple logo.
Now i know that it is tethered Jailbreak.
So i tried to keep the top button pressed to turn off the phone and it does not get turned off.

Now my best guess is to boot tethered and get it back in working condition...right ??
If yes then how do i put it into DFU mode and do a "JUST BOOT" so that it starts working again, given the condition that it is not shutting itself down when i keep the top button pressed ??

Yup "Just Boot" with redsn0w & you'll be fine.

[raksrules]

^^But how do i turn off the iPhone 4 before i do a JUST BOOT ??
As i said, it does not want to turn off, it is in sort of an infinite loop it seems.

[raksrules]

Restarted using JUST BOOT and it worked fine and it is also unlocked now