Can Iphone 3GS on iOS 4.0.1 be jailbroken?

[han_doi]

Can Iphone 3GS on iOS 4.0.1 be jailbroken?
I can only find guides for jailbreaking 4.0

[eyeRobot]

It can't be jailbroken at the moment, but we are expecting a new tool any day.

If you had SHSH files saved for 3.1.x then you could downgrade and jailbreak there. Further, if you have the old bootrom 3GS, once JB at 3.1.x you could use custom firmware to get back to 4.0 or 4.0.1

[han_doi]

What if you have an iphone 3gs never jailbroken, just upgraded to 4.0.1 from 3.1.3
Can that be downgraded and jailbroken?
What is the bootrom? thanks

[eyeRobot]

As I said above, it can't be jailbroken at the moment.

Bootrom info:
Apple Updates Boot ROM in new iPhone 3GS Models to Prevent Jailbreaking - iPhone Hacks