Hey there, not sure where to post this, I have a few questions..

I have an iPhone 3GS old bootrom on iOS 4.0.1 and Baseband 05.13.04 and I unlocked and had jailbroken it.
Now I would like to upgrade it to iOS 4.2.1 but without upgrading my baseband to 06.xx.xx is it possible?
will it stay unlocked if i use ultrasn0w after i jailbreak?
I'm using Windows 7..

Sorry for the trouble.. Thank you for your assistance.. :-)

Originally Posted by dagidag

Hey there, not sure where to post this, I have a few questions..

I have an iPhone 3GS old bootrom on iOS 4.0.1 and Baseband 05.13.04 and I unlocked and had jailbroken it.
Now I would like to upgrade it to iOS 4.2.1 but without upgrading my baseband to 06.xx.xx is it possible?
will it stay unlocked if i use ultrasn0w after i jailbreak?
I'm using Windows 7..

Sorry for the trouble.. Thank you for your assistance.. :-)

it is possible.
You MUST use the custom pwnage bundle - READ here Dev-Team Blog (under update #3)

It is a minimal bundle so after a restore using custom firmware 4.2.1 created with that bundle, you would need to run redsn0w 0.9.6rc8 to jailbreak + install cydia.

YOU NEED and must use a mac machine to create custom firmware 4.2.1 for 3gs old bootrom. No tool available for windows.

i wont go with all this trouble, idont have mac....
right now i have 4.0.1, is it possible to upgrade other newer version? in a simple way?
what are the differences between the ios?

dtube is correct, OS X/Pwnagetool is the only way. There is no other way. Pwnagetool custom IPSW is not difficult (but does require a mac)

as for diffferences from 4.0.1

iOS 4.0.2 for iPhone and iPod Touch and iOS 3.2.2 for the iPad were released on August 11, 2010, to fix a pair of security vulnerabilities.[18]

iOS 4.1 for the iPhone and iPod Touch was released on September 8, 2010; the update fixes some bugs reported by users, improves battery life and adds a new feature called Game Center, which allow gamers to multiplay, upload high scores and to unlock achievements (though, Apple removed Game Center from the iPhone 3G due to reports on slow performance) and adds initial support for the iPod Touch 4th Generation and the Apple TV 2G. iOS 4.1 also updated carrier settings which in the US was AT&T 8.0 and enabled toggling Check Spelling On/Off. iOS 4.1 also adds HDR photography,[19] a feature that only the iPhone 4 is capable of using. TV Show Rentals are available on the iTunes US Store. iOS 4.1 also adds a new feature called Ping which is a social music network and discovery tool.

iOS 4.2 was released to developers on November 8, 2010. It was never released to the public as a Wi-Fi bug was found during the limited release. Apple then issued two more golden master releases. Finally, Apple released iOS 4.2.1 to the public.

iOS 4.2.1 was released on November 22, 2010 with support for all Apple A4 devices, 3rd-, and 2nd-generation devices, with the exclusion of the Apple TV. It brings initial support of iOS 4.x to iPad, plus AirPlay and AirPrint to all compatible devices. It also contains minor changes to the YouTube app and alters the multitasking animation. On iPad, the screen rotation lock button's functionality changes to mute, the same as it was originally planned. As a known major bug, this version seems to hinder the usage of the Camera Connection Kit on the iPad.

if those are the differences why do people want so much to upgrade, i dont see 1 usefull thing in it...........

Originally Posted by dagidag

if those are the differences why do people want so much to upgrade, i dont see 1 usefull thing in it...........

:-)
Some people just want to have the latest just because they think it's the greatest.
I'm still using 4.1 on my IP4 even though i can put 4.2.1 & un-tethered it. 4.2.1 is not important.

with that said, some apps on appstore requires that you have 4.2.1 but not all of them have that requirement. If an app force me to upgrade to 4.2.1, i will simply NOT use it.