In late July I succesfully Jailbroke and unlocked my 3G iPhone running 3.1.3 and then sold it to my Brother in Law. He has been using it with T-Mobile since then. I used pwntool, then fuzzyband to change the baseband, and then ultrasn0w A couple days ago, he accidentally upgraded to 4.1 I tried to help him out today. I still had my custom .ipsw file I had made for him, and so I used pwntool to reinstall that .ipsw (3.1.3) That worked fine, but when I tried to use fuzzyband, it said something to the effect of "Does not work on Bootloader 05.09" Now, from what I've gathered, this means that the iPhone previously had 05.08 when I originally unlocked it, but now, due to the upgrade, it was changed to 05.09 But where I am confused is this. I keep reading everywhere that bootloaders are part of the hardware and CANNOT be changed. Do people simply mean bootloaders cannot be DOWNgraded, or can they really never be changed. Because if the can not be changed at all then I am really confused as to how I was originally able to change the baseband and unlock the iPhone. Everything I am reading says that 05.09 cannot be unlocked. Also, I purchased the phone whithin a couple weeks of launch, so that seems consistent with it originally having 05.08. So basically, I want to know if the bootloader was indeed upgraded when ios4.1 was installed. And also it based on everything I've read, my Brother in Law is SOL at least for now, correct? Thanks very much. I've been trying to figure this out on my own but often the info seems contradictory, or possible out of date.