How to Jailbreak iOS 4.2.1 with RedSn0w 0.9.6b4 - iPhoneHeat

How to Jailbreak iOS 4.2.1 with RedSn0w 0.9.6b4

Dev-Team has release RedSn0w 0.9.6b4 to jailbreak iOS 4.2.1 on iPhone 4, 3GS, 3G, iPod touch 4G, 3G, 2G and iPad. RedSn0w 0.9.6b4 jailbreaks iOS 4.2.1 with working Cydia and MobileSubstrate. Step-by-step instructions on how to jailbreak iOS 4.2 with RedSn0w 0.9.6b4 after the jump…
RedSn0w 0.9.6b4 is capable of jailbreaking all iDevices on iOS 4.2.1 however, newer devices are tethered jailbreak only. A tethered jailbreak means that each time your device loses battery power or needs to be rebooted, you must attach it to a PC or Mac to boot into the jailbroken state.

Untethered Jailbreak: iPhone 3GS (old bootrom), iPhone 3G, iPod touch 2G (Non-MC)
Tethered Jailbreak: iPhone 4, iPhone 3GS (new bootrom), iPad, iPod touch 4G, iPod touch 3G, iPod touch 2G (MC Model)

WARNING: unlockers please stay far far away from this official firmware (and all official firmware). Wait for the ability to create custom 4.2.1. IPSWs that don’t update your baseband! If you’re not an unlocker, read on!

Lets jailbreak iOS 4.2.1 firmware on iPhone 4, 3GS, 3G, iPod Touch 4G, 3G, 2G and iPad with RedSn0w 0.9.6b4.

How to Jailbreak iOS 4.2.1 with RedSn0w 0.9.6b4

Step 1

Step 2

Connect your iDevice to the iTunes 10.1 and restore iOS 4.2.1.
ATTENTION iPhone Users: iOS 4.2.1 will update your baseband which is not unlockable ATM.

Step 3

Once your iPhone / iPod Touch / iPad is running iOS 4.2.1, execute the downloaded RedSn0w 0.9.6b4.

jailbreak ios 4.2.1 redsn0w 0.9.6b4

Step 4

Hit the Browse button and select the downloaded iOS 4.2.1 firmware. RedSn0w will recognize the firmware, now hit the Next button.

jailbreak ios 4.2.1 redsn0w 0.9.6b4

Step 5

Now select your desired options. Make sure that atleast Install Cydia is selected. Now hit Next button.

jailbreak ios 4.2.1 redsn0w 0.9.6b4

Step 6

RedSn0w will ask you to turn off your device. When it’s off and plugged in, hit the next button.

jailbreak ios 4.2.1 redsn0w 0.9.6b4

Step 7

Now you’ll be instructed to put your device into DFU Mode. Follow the on screen instructions.

jailbreak ios 4.2.1 redsn0w 0.9.6b4

Once your device goes into DFU mode, RedSn0w will start jailbreaking it. Once done, you can find the Cydia icon on your iPhone / iPod Touch / iPad home screen.

That’s it. You’ve successfully jailbreak iOS 4.2.1 on iPhone 4, 3GS, 3G, iPod touch 4G, 3G, 2G and iPad with RedSn0w 0.9.6b4.

How to Boot Tethered jailbroken Device after reboot:

jailbreak ios 4.2.1 redsn0w 0.9.6b4

You can follow us on Twitter, Join us at Facebook, and also Subscribed to RSS Feed to receive latest updates.

Also checkout:

108 comments… add one
majditayeh November 23, 2010, 7:47 pm

it is not work on 3gs newbootrom

majditayeh November 23, 2010, 11:45 pm

jailbreak done,thanks to all

danishkhaleel November 24, 2010, 4:28 pm

redsnow giving me waiting for reboot & nothing to do then i press power & home button then giohng to update please tell me what to do my phone still not jailbreaking

najAF November 29, 2010, 6:44 pm

same problem with me any one help plz

St3vi3 December 15, 2013, 8:57 am

Change red snow to run in windows xp service pack 2

najAF November 29, 2010, 6:45 pm

its happenging with me too

sam2748 December 8, 2010, 5:09 pm

Could be because you didnt restore your ipod before jailbreak and had stuff on it e.g songs ect.

Henry November 23, 2010, 8:06 pm

This link is dead… or upload not done?

someone November 23, 2010, 10:02 pm

cydia work?

Kylie November 29, 2010, 4:02 pm

so, has the Cydia been working properly on 3GS now?

Quirin November 23, 2010, 11:33 pm

mirror 1 is dead …

mishendr November 24, 2010, 12:27 am

Done. Fully working. I’m under the impression 4.2.1 on my 3G is slighty more responsive.

ProeyJoey November 24, 2010, 2:03 am

I thought if you saved your SHSH you could have an untethered one for iPod 4g and stuffs.

Quirin November 24, 2010, 4:20 am

aparently not, hope they get it untethered quickly though

majditayeh November 24, 2010, 2:06 am

when the unlock for 5.15.04

AfRoO November 25, 2010, 2:01 pm

what the hell of 5.15.04 is,

indi November 25, 2010, 3:00 pm

LOL just upgrade locked 3G/S to 4.2.1

Henry November 24, 2010, 3:38 am

When to restore, i got message error like this:
“The iPhone “iPhone” could not be restored. An unknown error occurred (3014)”

What happened? Help me please…

me November 24, 2010, 3:57 am

redsnow keeps locking up halfway through, any ideas

GreenPois0n November 24, 2010, 4:32 am

it says it works for itouch 2g mc but redsn0w says otherwise says not compatible yet(never has been).

Ian November 29, 2010, 5:02 am

I had that issue on windows 7 64 – make redsnow run in XP mode

Roald November 24, 2010, 5:06 am

OK so how much longer for the unlock? and what about the people who lost the wi-fi on their phones due to an update will it be an unlock that not require Internet connection?

archer November 24, 2010, 12:31 pm

cydia faild installling

jucanor November 24, 2010, 6:21 pm

What are the basebands and bootrom that this Jailbreak will not unlock?

DaVoN November 24, 2010, 7:52 pm

Cydia is not work.

Gipot November 25, 2010, 12:48 am

I jailbroke my iPod touch 2g, its fine and cydia is fine, only error is the multi-tasking when i try to swap app my device shuts down.

AfRoO November 25, 2010, 2:02 pm

guyz i’m wondering about this jailbreak, what’s the effects with it?

Gipot November 25, 2010, 5:06 pm

What device do you have?

mishendr November 25, 2010, 5:54 pm

Well…. I earlier said that my 3G is fully JB, but I do get a lot of crashes, I’m constantly running in safe mode…. Waiting for some updates I guess…

iPadNeedsHelp November 26, 2010, 12:51 am

My iPad was working great after the jailbreak and such. Installous wasn’t working for me so I shut it off and tried to turn it bakc on. But, it didnt=’t work so I went ahead did the tethered boot. And it’s going swell.. then when it gets to waiting for reboot. My iPad isn’t responding to it; for some awkward reason.

noor November 27, 2010, 2:25 am

dead link 🙁
im not restore the new OS 4.2.1

iPhoneHeat November 27, 2010, 5:43 pm

links fixed

amanda November 27, 2010, 8:26 am

I have a iphone 4 and am not able to install winterboard once I get cydia to install. I keep getting the message of size mismatch

kennedy November 27, 2010, 4:36 pm

i want to buy iphone 4 can anybody help
me with that

matt December 8, 2010, 7:49 am


tonz November 27, 2010, 7:19 pm

I have a Iphone 3gs jailbroken unlocked firmware: 5.12.01 version 3.1.3 (7E18)

I don’t know if it’s old or new bootrom….
can i update to 4.2.1 and unlock with (new)ultrasnow ?????

please answer, i am a new one 🙁

thanksssssss 🙂

altecmayank November 27, 2010, 10:52 pm

Works Perfect with my Ipad . Hope untethering will hapeen soon. thank you

me November 28, 2010, 11:47 am

i have downloaded iOS 4.2.1 firmware . on to my computer but when run the jailbreak and browsefor the downloaded iOS 4.2.1 firmware, the correct file is not there. can anyone help me pleeeease.

draco809 November 28, 2010, 1:54 pm

guys if my iphone serial number’s 4th and 5th digit is 17, does it mean my 3gs is old bootrom?

Masrihy November 28, 2010, 9:23 pm

I tried it but the cydia didn’t work can you help me with this issue

KlauzOnFire November 29, 2010, 7:34 am

I Phone 3GS New Bootroom, jailbreak 4.2.1 works, but the Phone doesn’t boot 🙁 I’ve tried it with redsnow and the terethered boot, for a short time u can see the pinenapple than black screen and the normal apple logo and the connect Phone to Itunes picture 🙁

Need help please

najAF November 29, 2010, 3:21 pm

i had updated 3g to 4.2.1 and when it coplets phone start and ask for authorized sim card i dnt have this any other way plz help….

Golf November 29, 2010, 8:21 pm

Thanks a lot.

iphon family November 30, 2010, 9:49 am

it keeps freezing up in the exact same spot…get 11 bars into the screen Exploiting with limera1n and it won’t go any farther. Have tried over and over…HELP

xteknox March 3, 2011, 11:06 am


nick_limens December 5, 2010, 8:33 am

stuck also at the screen “Exploting with limera1n”, won’t go further too. need HELP

prettyboy17 December 15, 2010, 10:15 am

ei nick, have you now jailbreakd ur ipod?,

prettyboy17 December 15, 2010, 10:17 am

ei nick, have you now jailbreakd ur ipod?, i also got freeze in exploiting limera1n, hey iphoneheat?, whats is oour problem why is it that we cant jailbreak our ipods?

j_sol December 7, 2010, 2:19 am

I have an iphone 4 with 4.2.1 installed. Tried using RedSn0w 0.9.6b4 but it keeps freezing and redsnow stops working ! Any ideas please

wicked_sam2 December 7, 2010, 7:22 pm

its not working for my 8gb MC model ipod touch 2ndGEN..says `this version does not support 2Gen ipods mc models yet`..even tried running in different compatibility modes..wat to guys…

iPodNub December 9, 2010, 2:04 am

I am also getting the “Exploting with limera1n” freeze. It’s exactly halfway through the JB when it stops here. I am using a iPod Touch 3g.

chris2244 January 17, 2011, 10:47 pm

I am having same problem with same device please someone help us.

bekah143 November 20, 2011, 4:14 am

Same here! Im getting really frustrated with this!

iPhoneHeat November 21, 2011, 3:08 pm

Try latest RedSn0w:
try another USB port or computer

KT790 December 11, 2010, 8:19 pm

Ok. So I jailbroke my ipod and i have cydia and stuff but how do i get all the apps to be free?
Where do i go on Cydia to get the package to get all the free apps?? 🙁 please help!!

KT790 December 11, 2010, 8:23 pm

I jailbroke my ipod touch 2nd gen. on, 4.1 with greenposi0n.
I’m on cydia, and how do I get all the apps in the app store to be free?!?

I don’t know where to go!

soyye December 15, 2010, 2:50 am

I have a 4G 4.2.1 factory unlock Iphone.. have done jailbreaking using iOS 4.2.1 with RedSn0w 0.9.6b4..however, if i turn off and turn it on it stuck with apple logo and does not go any further. Again, I have to restart using tethered to access my phone..have restored to original firmware three times and jailbroken and same thing happens


spultx December 19, 2010, 2:15 pm

Same problem for me 🙁 HEEEEELLLLPPPPPP…!!

nate January 4, 2011, 4:32 am

cydia isnt working. its just a white application

dakotaboker January 8, 2011, 2:50 pm

ok. the i clicked on the cydia and nothing came up on my ipod.Help?

proud2bazn January 10, 2011, 11:35 pm

just email me and ill send you a new redsn0w0.9.6b5 not redsn0w0.9.6b4. my email is
[email protected]

Scottb January 17, 2011, 7:56 am

RedSn0w freezes part way through jailbreak for ipad. Can anyone lend any advice ?? followed steps above with no problem until the freeze.

akire February 4, 2011, 11:16 am

ok i have an iphone 3g ios 4.2.1 with the 06.15.00 baseband and i cannot multi-task. when i try it goes into safe mode. i jailbroke with redsn0w redsn0w0.9.6b5. anyone have any suggestions or solutions.

shottayouth February 6, 2011, 11:37 pm

downgrade back to 4.1
i had the same issues and couldn’t take the it safe mode message any more
have had no issues since i’ve downgraded
i have my shsh blobs saved for all firmware from 4.0 so i start tiny umbrella
i then use redsn0w 0.9.6b6 to enter dfu mode “that’s the only option ticked”
i open itunes and “device in recovery mode detected” comes up
i restore with a custom firmware from pwnagetool and then run thru the process of updating cydia, installing SAM and unlocking with ultrasn0w
not sure if it will work for you but its perfectly working for me
am using windows 7 btw

scotty February 5, 2011, 8:02 pm

mine gets to the end and says windows has stopped workin we are now closing program.. what do i do?

Rami Shareef February 9, 2011, 6:20 pm

I’ve already updated my OS through Itunes and now my iPhone 4 running OS 4.2.1, dose this process works for me too or I’m going to lose my data after jail-breaking?
please advice

Adam the of king February 14, 2011, 7:15 pm

Thanks! worked great!!!

dinarian March 4, 2011, 7:03 am

Guys my iphone 3gs which i got it from uk is struck on the boot screen after i tried erasing all the data, kindly help i tried, holding home and the power button option, and the iphone is not being detected by the i tunes as well pls help me

melzz March 5, 2011, 11:56 pm

my iphone 4 could not connect to itunes after installing the jailbreak.
please advice me what to do.

iPhoneHeat March 6, 2011, 2:30 am

check your USb cable. May be try another one.
Or plug it into another computer.

ijulvienoz April 20, 2011, 6:43 am

hi,, my firmware of iphone 3g is 05.15.04. but why i can’t jailbreak use that?? please help me i’am newbie

lakshit May 25, 2011, 10:23 pm

always get hang on uploading ramdisk after dfu mode

xXfllnXangelXx May 26, 2011, 2:38 am

i went through red snow mirror 1 and my device is a 2g one and cydia isn’t loading on mine is it my iOS or the red snow btw im using windows

amateuriphoneuser July 30, 2011, 3:55 pm

anybody can help me? after all the step completed, the time my iphone 3g reboot, the apple icon show up not pineapple icon show up…. then the iphone jus cannot boot up and hang in boot up apple icon…..

Guntaey August 16, 2011, 9:22 pm

Matur suwun gan 3Gku wes isoh dijailbrake.. uapik tenan tutoriale..

jbchong1258 October 1, 2011, 6:03 pm

pls help me my iPod did not jailbreak……and it hanged

Rehman July 13, 2013, 1:58 pm

download a software which has jailbreaked and then install it through iTunes 9.2 the website I have written which u can download jailbreaked software

bekah143 November 20, 2011, 4:05 am

it won’t finish completing the jailbreak. its been frozen for hours. i’ve tried it two times. Now it won
t turn on. What should I do? I need help!

mike10422 August 14, 2012, 6:13 am

plug it in to the computer using iTunes an restore your device. That’s what happened to me at first so i restored it.

Overdone April 3, 2012, 2:25 am

my firmware will not show up in any files when I load up redsn0w, I have already downloaded it and saved it to computer.

swagxxman June 9, 2012, 1:50 am

thank you very much developers you are the first to help me thanks

mike10422 August 14, 2012, 6:12 am

Thank you very much. It worked just fine for me

sharippe September 24, 2012, 6:10 am

its stuck at uploading ramdisk

JImmys81190 December 4, 2012, 6:25 am

Cydia is asking me to update, how do I go about doing this? Any links you could direct me to?

FuutonNaation January 3, 2013, 1:01 am

in the redsnow application, after i try to enter DFU mode it just says “Exploiting with limera1n” and just stays there, what do i do?

Turza February 22, 2013, 9:56 pm

after doing all of this icant fina a cydia icon on my i phone 3g….

Michael June 8, 2013, 11:02 am

how long it will take donwloading jailbreak data

nicole September 21, 2013, 8:54 pm

i cant find the cydia app either i have this twice already and no app please help

Jasmin August 7, 2014, 12:53 am

hi, ive been trying to jailbreak my ipod touch 3g ios 4.2.1 with redsnow and i do every step but it always freezes at limera1n and i dont knpw what to do

safa February 8, 2015, 2:29 am

for me its works till the device being processed part however its taking wayyy too long and it wont update

Leave a Comment