Redsnow is easy to use, it is available for Windows and Mac OS. Pwnagetool can be used to create custom ipsw and preserve baseband, it supports Mac OS only.
Ultrasn0w doesn’t work on iOS 4.3.1 yet (even with iOS 4.3.1 + old baseband). The fix will be available soon. Here’s a warning from DevTeam for unlockers:
Can not wait for the official release? Do you want to get CineXPlayer for iPad on your iPhone and iPod touch right now? For those of you who do not know, CineXPlayer is an iPad application that allows you to download Xvid AVI files using iTunes, so you can easily reproduce the format that Apple won’t. Because the developer has not invented version of the application for the iPhone, the hacker decided to do everything by himself.
It is a complete step by step tutorial on how to install it on your iPhone or iPod touch available here. You just need to jailbreak these devices, because the process involves SSH (SSH program for secure file sharing on the network) to access the iPhone, but it’s worth it if you want to get it right now!
Go to /private/var/root/Library/, delete original lockdown folder and put this lockdown folder after you extract it from the zip file
Restart phone
If you are not jailbroken:
Sherif Hashim discovered that you can activate your iPhone 4, iPhone 3GS or even iPhone 3G without the original carrier SIM card. You need a “phonebook sim card” or 02 simcard. You can buy these type of sim at radioshack, bestbuy or other mobile electronics store (for example here).
Once you get passed the Emergency Call screen, connect to Wifi, jailbreak using JailbreakMe.com and unlock using ultrasn0w. Once that is complete you should be passed activation and unlocked (able to use any sim). If you get a different simcard error, do the following final step:
Go to /private/var/root/Library/, delete original lockdown folder and put this lockdown folder after you extract it from the zip file
Restart phone
If you have itunes invalid response problem:
Connect to wifi and ssh to your phone (via winscp, putty, terminal, etc).
Navigate to your lockdown folder (/private/var/root/Library/).
Delete pair_records folder
Reconnect the cable and see that your invalid response problem is gone.
If you bought your iPhone 4 on ebay you will need the official sim (at&t) or a universal sim, like ones you can grab at bestbuy for $10 this will get you passed Emergency Screen.
When asked about PwnageTool, MuscleNerd said via twitter “they can compile now for wxwidgets for redsn0w 0.9, so pwnagetool port can be based on this”, “and so that means, pwnagetool port for windows and linux. For OSX it’s all on @wizdaz of course ”
PwnageTool lets you build custom ipsw files which can include personalized boot logos as well as automatic installation of applications. There is also project called Sn0wBreeze, a port of PwnageTool to Windows. However a port from DevTeam is of course more preferrable.
The latest version of PwnageTool 3.14 can be downloaded here.