Preseve iOS4 baseband?

[definitive]

I have an iPhone 4 with 4.3.3 and original 1.59 baseband. Is there a way at the moment to upgrade to iOS5 and preserve the baseband? I remember doing it for 4.3.3 with TinyUmbrella, but not sure if that will still work now...

 

[Applejuiced]

Yes, I think TU has been upgraded to preserve your baseband while updating to 5.0

 

[Nawizo]

I would like to know the steps to follow when using tinyumbrella. Pliz provide me with links for all the necessary software. Does preserving your baseband necessarily mean u have to jailbreak yo phone? Or is it tht on updating/restoring your software it just preserves yo baseband but yo phone remains unjailbroken and ther is no need to boot from the pc all the time. If using tiny umbrella will work please provide me with the instructions of how to do it