May 21, 2024
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Posted November 23, 2010 at 5:49pm by iClarified
These are instructions on how to jailbreak your iPhone 4 on the 4.2.1 firmware using RedSn0w for Mac. You will only be able to perform a tethered jailbreak at this time. This means you will need Redsn0w's assistance to boot into your jailbroken device.

If you want to jailbreak a lower firmware version you can find the appropriate tutorial here.

Make sure not to update to iOS 4.2.1 if you need an unlock as one is not yet available!

Step One
Create a folder on your desktop called Pwnage

Download RedSn0w from here and place it in the Pwnage folder. Likewise, download the latest 4.2.1 firmware from below and place it in the same folder.

4.2.1 (4): iPhone3,1_4.2.1_8C148_Restore.ipsw

Extract the redsn0w app from the RedSn0w zip file by double clicking it.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Two
Connect your iPhone to the computer and launch iTunes.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Select your iPhone from the list of devices on the left. Now hold down Option and click the Restore button. Restore is preferred as it won't create any wasted space on your iPhone.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Navigate to the Pwnage folder on your desktop and select the 4.2.1 firmware ipsw. Click the Choose button to continue.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Three
Once iTunes has finished updating your iPhone to the desired firmware open the Pwnage folder on your desktop and launch the redsn0w application from the redsn0w folder we extracted earlier.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Four
Once RedSn0w opens click the Browse button
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Five
Select the 4.2.1 firmware ipsw we placed in the Pwnage folder on our desktop then click Open.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Six
Once the firmware has been verified click the Next button to continue.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Seven
RedSn0w will now prepare the jailbreak data
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Eight
From this window you can select the jailbreak options you would like.

Make sure Cydia is selected and click the Next button to continue
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Nine
Please plug your iPhone into the computer and make sure its OFF then click the Next button
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Ten
RedSn0w will now guide you through the steps to get into DFU mode. You can find more help with DFU mode here
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Hold down both the Home button and the Power button for 10 seconds.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Release the Power button and continue holding the Home button until RedSn0w detects the device.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Eleven
Your iPhone will now reboot
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Twelve
RedSn0w will then begin uploading the new RAM Disk and Kernel.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

Step Thirteen
Once this is complete you will be notified that RedSn0w is done. Click the Finish button. When your iPhone finishes rebooting (5 minutes or so) it will be jailbroken with Cydia on the SpringBoard.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

To use Redsn0w to help you boot back into your jailbroken device simply select Just boot tethered right now from the options window and click Next.
How to Jailbreak Your iPhone 4 Using RedSn0w (Mac) [4.2.1]

*As usual a big thanks to the iPhone Dev-Team for their hard work and contribution to the iPhone community.
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Comments (48)
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modemode55 - January 8, 2013 at 8:57pm
gooooooood thx
Brock - February 14, 2011 at 1:43pm
I have an iphone 4 version 4.2.1(8C148) with firmware 03.10.01, all I want to do is Jailbreak it and not unlock it because I have AT&T. on other comments I've seen that this updates the baseband... will this void my factory warranty and applecare? thanks!!
范駿 - March 24, 2013 at 10:16pm
Arif - January 24, 2011 at 5:55pm
Hi, i just jailbroken my iphone 4. the cydia is installed, but its white app. not brown as it should be. when i click on it the cydia does not open nor safari. can anyone help me. i have macbook, mac os x leopard.
Tony - January 23, 2011 at 12:44am
I did the steps to jaibreak and cydia works fine when tethered, but Safari does not work??? opens and closes right away.
Elaine - November 24, 2012 at 6:48am
Wow! Great tikhning! JK
sarvary70 - January 15, 2011 at 4:12pm
Hi. Thanks guys, I am having a problem with jailbreak my iPhone4, I got my iphone a couple of days beforre officially on 4.2.1, tried so many times jailbreak it with redsnow but no success. what happens? after this procedure my iPhone4 reboots then everything is well, Cydia is white icon and when i press on it nothing happens. Any respond and idea will be nice and appreciated. regards
Tashi - January 10, 2011 at 3:13am
i Jailbroke my iphone 4 [version 4.2.1(8C148), firmware 03.10.01] using the latest Redsn0w mac 0.9.7b5 but having problem with Skype not loading. I tried the jailbreak process again to see if I was not doing it right but all apps seems to working fine except Skype and Watsapp. Just wanted to inform the dev team about the glitch. Thanksks for all the great work.
Kitten - December 29, 2010 at 4:28pm
ive tried downloading the restore software but it shows it will take several hours to download - why is this? is there a different link i can use? thanks!
AXam - December 25, 2010 at 2:38pm
Thanks so much Dev-Team will contribute more and loads of love thanks guys for the hard work
Daniel - December 22, 2010 at 4:08pm
Hi.. I've got an unlock iphone and it was already running 4.2.1 without JB. I tried to JB with redsn0w and followed all the steps in the tutorial, but when the iphone is doing its first reboot while in the process, it freezes.. I reboot it manually and start it back.. and i use the redsn0w app so that the phone start.. but when he starts, i don't have any network carrier :( and i can't even do a restore via iTunes, cause it says that my device isn't compatible.. how can i solve this out ? thanks!
Arturo - December 21, 2010 at 7:50pm
Hey Guys, I have an iphone 4 i did jb but when i put the ship to another company it doesnt work. so, i still cant use my iphone with different company provider. Could u guys please help me out? Tks Arturo
dadabryan - December 19, 2010 at 8:48am
thank you iPhone Dev-Team! it's works for me. i jb with iphone4 running 4.2.1 firmware.
DjSha - December 19, 2010 at 12:01pm
Hoe did u get passes the network problem?
GOld - December 18, 2010 at 6:34pm
Hello Iclarified team Thank you for your support. I got it, with jailbreak was OK. Next question , how i can unlock my phone ? sorry for my disturb by the way my baseband before upgrade was 01.59 and now 03.10.01 it's ok or no ?
GOld - December 18, 2010 at 7:18am
Hello need your help. jailbreak 4.2.1 also unlock as well. redsn0w wrote that unable recognize specified IPSW what's wrong ?
Don Buenaventura
Don Buenaventura - December 18, 2010 at 3:38am
Is there available jailbreak for iPhone4 with IOS 4.2.1 on OS Tiger 10.4.11? I downloaded the Redsnow jailbreak for iPhone4 IOS4.2.1 but when I double click it it say " it is not supported in this architecture?." Thanks.
Gary - December 14, 2010 at 1:33am
All steps followed but I keep getting stuck at reboot. Can anyone please help?
Sunny Lai
Sunny Lai - December 14, 2010 at 7:47am
all, I think the first step is that you need to upgrade the OS to 4.2.1 completely. Then, you can follow this procedure to JB your iphone 4. Otherwise, it might not work. This is my experience for sharing.
Clint - December 10, 2010 at 2:07am
I just got an iPhone 4 on Mon and had a problem with the JB. I used Pwnage to JB my 3G with no problem, but can't get past Step 2 here for Redsn0w. Exact Message is: The iPhone "NAME REMOVED" could not be restored because the firmware file is not compatible" with the options of [More Information] or [OK]. Anyone know the remedy for this? I'd really like to fix this.
Clint - December 10, 2010 at 11:10am
I did use Firefox. I am running OS X 10.6.4 Snow Leopard and thus do not have IE. I will try again, however, the only real need I have for JB is SBSettings so I can easily toggle brightness, Wi-Fi and Bluetooth and I guess if I ever need to unlock(even though there isn't one currently available for iPhone 4 firmware on 4.2.1).
kiva - December 10, 2010 at 2:02pm
this is the same problem i'm having. I guess i'll wait for another JB and try later.
gsrao - January 11, 2011 at 12:48am
use safari .it will work fine
Bardia - December 7, 2010 at 5:55pm
Hello...!!! i jail broke my iphone and i made a cydia on my iphone 4, but when i rebooted it, cydia didnt work anymore! :( ( i tried to do that about 5 times!!! ) . . . Any Help?!?!?!?!?!?!
Dj Sha
Dj Sha - December 6, 2010 at 11:03am
jailbreak is gone ok, but i don't have any network more(i can't make a call etc.) Does someone has the solutions for this?
Dj Sha
Dj Sha - December 25, 2010 at 2:44pm
Ok, you don't know the answer
Bill - December 5, 2010 at 2:17pm
This will lock your phone. It will update your baseband to the most recent, so don't do it if you need to unlock iy.
ray - December 5, 2010 at 5:02am
my iphone will not cut on after i installed cynia and jail broke it. any suggestions?
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