how to change baseband from 06.15.00 to one that will allow iOS5 beta

[shandyman]

Can anyone help? my mate got his baseband changed for an unlock by someone, but want's iOS5 on it, i know the baseband has to be dropped, but neither of us have jailbroken before.

Help!

 

[Intell]

Once you upgrade the baseband to 6.15.00, you cannot go back down. Ever.

 

[Applejuiced]

You cannot.
You will have to wait for a custom jb Ipsw.