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Jailbreak iOS 4.2.1 Untethered on Windows greenpois0n RC 5

Written By Unknown on Saturday, February 5, 2011 | 2:33 PM


greenpois0n Windows RC 5 download The greenpois0n RC 5.2 untethered download for Windows has now been released by the Chronic Dev Team. You can download greenpois0n Windows RC 5.2 from the greenpois0n page. This version is compatible with the following devices on iOS 4.2.1:

  • iPhone 4 - 4.2.1

  • iPhone 3GS - 4.2.1

  • iPod touch 4G - 4.2.1

  • iPod touch 3G - 4.2.1

  • iPod touch 2G - 4.2.1

  • iPad 1G - 4.2.1

  • Apple TV - 4.2.1

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Jailbreak iOS 4.2.1 Untethered with Greenpois0n Windows RC 5.2 Tutorial

1. Download greenpois0n for Windows, then watch this video or follow the instructions below.

2. Make sure you are using the latest version of iTunes (currently that is version 10.1.2) otherwise you won't be able to do a 4.2.1 untethered jailbreak. To do that go to iTunes - > Check for Updates.

3. Connect your iOS 4.2.1 device to your computer using the white USB cable.

4. If iTunes opens, make sure you close it!

5. Open the greenpois0n Windows RC 5.2 application to begin the jailbreak iOS 4.2.1 untethered process.

6. Follow the instructions within greenpois0n Windows RC 5.2 so you can get an untethered iOS 4.2.1 jailbreak, first click the "Prepare to Jailbreak (DFU)" button:

  1. Press and hold the sleep button (2 seconds)

  2. Continue holding sleep; press and hold home button (10 seconds)

  3. Release sleep button; continue holding home button (15 seconds)

7. After following step 6, your device will be in DFU mode and greenpois0n will start jailbreaking iOS 4.2.1 untethered on your device.

8. Once your device is successfully jailbroken untethered on your iOS 4.2.1 software, then your device will reboot and you will see a green icon named "Loader" on your device.

9. Tap on the green "Loader" application to open it, and then tap on Cydia and tap on "Install" to install Cydia. Now Cydia should be on your iOS 4.2.1 jailbroken untethered device, and you should be able to install jailbroken apps on it.


  1. Cydia does not show up on my iOS 4.2.1 untethered jailbreak device after using Loader? - Try rebooting your device and seeing if it shows up. I had to restart my iPhone 4 and it showed up after rebooting.

  2. greenpois0n is stuck on greenpois0n initialized and has the following error message:

    • unable to find gBdevList

    • unable to find fs_mount

    • unable to find fs_unmount

    • unable to find fs_load_file

    • The above problem did not occur on my device. If anyone had this problem, please be sure to share how you fixed it in the comments so other people can fix this problem if they come across it as well. UPDATE: Greenpois0n RC 5.2 is released, and should fix this problem.

  3. greenpois0n 1.0 RC 5 Quit Unexpectedly - Just relaunch it and try it again!

  4. Loader is not installing Cydia - Due to many other users like you, the server which hosts the Cydia download is overloaded. I recommend trying downloading some other time, or you can just use redsn0w 0.9.6 rc8 and install Cydia through that. It’s very easy to use redsn0w and install it and that’s what other people seem to be doing too right now.

How did greenpois0n Windows RC5.2 work for you? Were you able to successfully untethered jailbreak iOS 4.2.1 on your device? Let us know in the comments below.


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+ comments + 97 comments

February 5, 2011 at 3:10 PM

Does this work for MC model iPod Touches?

February 5, 2011 at 3:28 PM

Before installing ver 4.2.1 in iTunes, download AptBackup in Cydia then open the AptBackup application and press backup bottom. Then connect to iTunes and perform a backup of your iPhone. After the backup, then update to OS 4.2.1. Close iTunes and download and extract greenpois0n rc5. After Cydia is installed then open iTunes and perform a restore. After the restore is complete open Cydia and install the AptBackup application. Close Cydia and open the AptBackup program and push the restore button. Upon completion of the restore procedure restart your iPhone. After restart all of your previous installed Cydia programs and settings should be restored.

February 5, 2011 at 3:35 PM

Thank you.. it works like a charm on the first try..

February 5, 2011 at 4:05 PM

Worked second time round, is running as well as the HEAT are!

February 5, 2011 at 4:07 PM

worked great for me as well been waiting for this since before christmas

The Captain
February 5, 2011 at 4:44 PM

Worked like a charm! Awwwwww yeahhhh! I went from redsn0w to GP without restoring and it worked if anyone wanted to know :)

February 5, 2011 at 5:31 PM

Windows file is a virus?? wont do anything for me?

February 5, 2011 at 6:43 PM

got these errors

unable to find gBdevList
unable to find fs_mount
unable to find fs_unmount
unable to find fs_load_file

but somehow the installation went though, is there something i should be worried about?

February 5, 2011 at 7:39 PM

Worked perfectly the first time! Thank you!

February 5, 2011 at 8:04 PM


hey, what do you mean with:

"Then connect to iTunes and perform a backup of your iPhone"
how can i do that?

February 5, 2011 at 8:04 PM

worked 3rd time around and relieved alot. thanks team,.

February 5, 2011 at 8:12 PM

Sorry but I cannot jailbreak my iphone 4 4.2.1...greenpoison just wont start after DFU.."jailbreak failed"..anyone know a how to?

chris chong
February 5, 2011 at 8:49 PM

hey..nice to meet u...izit really can do it with redsn0w tethered to GP without any problem? And izit the app that in cydia will work as well and no nid to reinstall again? =)

February 5, 2011 at 8:51 PM

After jailbreaking, my keyboard no longer appears in any app except cydia. not even in email, text, safari...nothing. any ideas?

February 5, 2011 at 9:19 PM

guys im using redsnow0.9.6b6 tethered version right now do i need to restored my iphone4 first to use this to have the untethered or can just do it right away?

February 5, 2011 at 9:21 PM

won't even start jailbreak. help? anybody? just stays at Jailbreaking... and never loads.

February 5, 2011 at 9:54 PM

cydia is much to slow. I am getting a posix operation time out everytime i download something.

Iphone 3G
February 5, 2011 at 11:08 PM

is greenpois0n RC 5 can jailbreak iphone 3G?

February 6, 2011 at 1:57 AM


I got the same errors but finished installation too.. Far as I can tell I'm jailbroken.

Is there anything we should be worried about? Anyone??

February 6, 2011 at 3:24 AM

This worked as perfect as it can! The first try failed, but the second try was a great sucsess! The only problem i had was that i couldn't find the Loader because all my folders where deleted from the 4.2 update, and all pages was filled.. xD

February 6, 2011 at 4:02 AM

CYdia is in my ipod desktop but when i open it it doesnt open!!!can anyone help?

February 6, 2011 at 4:06 AM

Yes. you need to restore first.

chris chong
February 6, 2011 at 5:12 AM

izit wont work if straight do it from redsn0w 0.9.6b6 to untetethered? Got any1 try b4? =)

February 6, 2011 at 5:31 AM

Plz can upgrade my soirit jailbroken iphone 3gs 3.1.3 to 4.2.1(7E18)then jailbreak using Greenpois0n Windows RC 5.2 ....plz help!!!!!!

February 6, 2011 at 5:49 AM

yes, i tried that. And it works fine. No need to fresh restore. :)

February 6, 2011 at 6:00 AM

and yes, the cydia and apps that u had been installed with redsnow0.9.6b6 will still be there. No worries! Pecfect!!!

February 6, 2011 at 7:07 AM

Plz can I upgrade my spirit jailbroken iphone 3gs 3.1.3 to 4.2.1(7E18)then jailbreak using Greenpois0n Windows RC 5.2 ….plz help!!!!!! Has anybody done this please help!!!!!!

February 6, 2011 at 7:55 AM

I have the same error... and I don't know how solve it....

please let me know if you find a solution!

Many Thanks!!!

February 6, 2011 at 8:46 AM

Got it to work tha first time round however Modmyi does not show up in the cydia repo list. Tried to Sizdoad it via winsc but nothing. Anyone have any suggestions? I can't download my3g or myfi since the repo is not there HELP!!

February 6, 2011 at 10:47 AM

Jailbreak fail Rebooted many times and Cydia was still completely broken if you have iPod touch 4.2.1 3rd gen. MC
P.S. The Skull rotating apple things sucks and looks terrible when your rebooting

February 6, 2011 at 11:26 AM

If you have any apps installed through Cydia, such as Intelliscreen or makeitmine, these will all be gone after 4.2.1 update and Jailbreak, so make sure you know where to find these apps again to save the the time hunting for them afterwards... On the up side, JB worked for me, first time, no problems, thanks Chronic Dev Team!

February 6, 2011 at 12:08 PM

Bug with iBooks!!!! I jailbroke my iPhone 4 and my iPod touch 4 and I have the same problem with both of them, when I open iBooks and try to read books that I purchased in the store it gives me this error "there is a problem with the configuration of your iPod touch/iPhone. Please restore with iTunes and reinstall iBooks". I only have problems with books I bought on the store, books that I converted to ebook from PDF still work fine, anyone else having this problem??

February 6, 2011 at 1:39 PM

Great News!
After Restoring my iPod touch 3rd gen. 32 gig. Mc model running on 4.2.1 firmware I have gotten a failed jailbreak instead of broken cydia. Isn't that just great?!

Specifics; First cydia would close up everytime I opened it and said that it would be fine if I re-opened cydia and tried again, I tried multiple times and it didn't work so I restored my IPod, tried to reinstall cydia and It said the jailbreak failed.
[EDIT: We don't take donations, any donations you made on greenpois0n.com went to ChronicDevTeam!]

That will be all ;)

Jacob Shade
February 6, 2011 at 1:43 PM

Jailbreak failed on my iPhone 4 (4.2.1). Device became stuck on the greenpoison loading symbol, rebooting made it stuck on apple loading symbol, tried jailbreaking again to same result. Restoring my device now to try again.

February 6, 2011 at 2:00 PM

Saah jeilb rake duhw snot wirch

thank you for reading

February 6, 2011 at 2:01 PM

Unable to find files and Cydia crashes immediately everytime I try to open it.

February 6, 2011 at 3:00 PM

JB with GP for 4.2.1 seemed to cause paid books in iBooks not to work. Hopefully the ChonicDev Team will fix this problem.

February 6, 2011 at 3:31 PM

can my iphone 4 shutdown when i install this jailbreak?

February 6, 2011 at 3:38 PM

Worked fine with me using the rc5 release. but still having problems with ibooks not opening protected files bought from the ibooks store. any workarounds??? thanks.

February 6, 2011 at 3:49 PM

On my iPod touch 2n gen mc model, every time I start up cydia, it crashes, reboots and re-jailbreaks don't work, what now?

February 6, 2011 at 3:51 PM

Getting Virusalert for Greenpois0n.exe:
Gen:Variant.Adware.Smshoax.9 (Engine-A)
I'm using G-Data IS, anyone other with this warning?

February 6, 2011 at 4:01 PM

The jailbreak worked just fine for my iPhone 4. First time no issues. THanks much!

Titi Berloge
February 6, 2011 at 6:42 PM

Jailbreak with redsn0w and after that use greenp0ison.
Cydia package is allready installed by redsn0w.
For me it worked like a charm.

February 6, 2011 at 8:53 PM

To jailbreak the iPhone worked..
But my springboard crashes all the time now! :-(
Never experienced this with 4.1 and the former jailbreak, redsn0w..

February 6, 2011 at 9:51 PM

jailbreak with green poison worked with me on iphone 4 4.2.1 but i still cant unlock the sim card with ultra snow... any suggestions?

February 6, 2011 at 11:18 PM

Worked fine for me and first attempt.I am a novice at these things and had no problems. Thank you guys

February 7, 2011 at 2:04 AM

Just so everyone knows aTV still isn't supported in greenpoison RC5... Your going to have to wait for RC6

February 7, 2011 at 2:40 AM

Worked perfectly!

February 7, 2011 at 2:50 AM

Hey Shark, ur doing alot of bitching and complaining, when the C-Dev team has been hustling to make a untethered jb, when everyone else thought it would be quite impossible to accomplish, everyone was whining then when we had to use redsnow 0.9.6 and have a tethered jb, then when they came out with a untethered jb for mac with redsnow and greenpois0n, ppl kept bitching "why?? why?? why cant u make a windows version?" well they did, right now im using a 3GS 32gig with 4.2.1, u have to restore to original 4.2.1 to run the jb,patience is a virtue, plz learn to use it, these ppl dont make money doing this, except from donations to keep their sites up to help us and keep us informed

February 7, 2011 at 2:54 AM

Unlocking iPhone 3gs on 4.2.1. Greenpois0n doesn't recognise DFU mode - I keep getting the "try again" message but if I go back to itunes, it tells me the device is in recovery.
Not sure what to do??

February 7, 2011 at 3:56 AM

got Some Problem, using iPhone 3G here. any programs that we need to make sure it closed first, just like using blackrain b4?

chris chong
February 7, 2011 at 4:01 AM

oh thanks, it work successfully, but get those error when installed:

unable to find gBdevList
unable to find fs_mount
unable to find fs_unmount
unable to find fs_load_file

izit fine with that?

February 7, 2011 at 4:16 AM

Same for me - iBooks no longer works just like you say. PDFs and non paid books still open ok but anything bought gives the same error you posted "there is a problem with the configuration of your iPhone. Please restore with iTunes and reinstall iBooks" Let us hope this is the only problem caused by the JB, and that they fix it soon :-) (iPhone 4 v4.2.1 - Jailbroken with Greenpois0n RC 5.2)

February 7, 2011 at 4:16 AM

I got that errors too but up until now no problem! So i think it should be fine. :) no worries no worries!

Reed Rothchild
February 7, 2011 at 7:13 AM

FYI.... I was already jailbroken (tethered) with redsn0w.... I simply ran the untethered Greenpoison jailbrake and everything was fine..... cydia was still installed and all my jailbroken software was still in place..... pretty simple.

February 7, 2011 at 8:38 AM

Greenpois0n is not compatible with iphone 3G, or early itouch versions, try Redsn0w 0.9.6 tethered jb

February 7, 2011 at 8:48 AM

sometimes on sum early 3GS models, u have to keep holding the home button to keep it in DFU mood

February 7, 2011 at 10:23 AM

If you see this:

1.unable to find gBdevList
2.unable to find fs_mount
3.unable to find fs_unmount
4.unable to find fs_load_file

Just don't touch anything for a few minutes. Mine finally worked. This is not for the impatient people out there;) Just follow the steps then walk away for awhile. Come back in 10 min and voila!

February 7, 2011 at 11:38 AM

I jailbroke my Ipod Touch 4th gen 32gb and now when i plug it into the computer, it charges but wont show up or sync with itunes! why not???

February 7, 2011 at 12:43 PM

Hi There.

Had to do the install twice, on iphone4.
Tried it on the ipad 4.2.1 worked perfectly.

Cheers Dev Team.
Whens the unlock coming out for BB 02.10.04????????

February 7, 2011 at 7:00 PM

Hey , mine is 4th gen too . Mine is kinda uhh ... I wonder if you solved yours already . Cos when i press , The picture in my itouch was the USB and the itunes logo sign ! It scare me ... I thot my itouch is going to die . Haha .

February 7, 2011 at 9:53 PM

It works perfect;) tks a lot!

February 7, 2011 at 10:33 PM

Heliguy's post is correct. I got the above message on my 4.2.1 3gs but if you check the greenpois0n status bar, it is still moving. After 5 minutes, it started to move.

My kudos to Chronic Dev team for bringing out this windows version of greenpois0n

Ernie Rea
February 8, 2011 at 2:00 AM

I had the same issue with it sticking on a blank screen saying
unable to find gBdevList
unable to find fs_mount
unable to find fs_unmount
unable to find fs_load_file
it sat for a min, and started working?
Every thing seems to be working fine now, thanx

February 8, 2011 at 3:51 AM

iBook issues with my 3rd gen itouch. Everything else seems fine.

February 8, 2011 at 6:35 AM

It worked perfectly on my iPhone 4...

Although I did have some issues updating to iOS 4.2.1. It stuck the phone in restore mode, giving me a "restore error 1013 (or 1611)". Eventually, I had do the following:

1. Go to c:\windows\system32\drivers\etc\hosts

2. Click on "Open With..." and then click on "Notepad" on the list.

3. Remove the entire line that has: "gs.apple.com" completely and save the file.

4. Restart iTunes and the updating should work smoothly, though you will have to re-install your pictures and music, manually.


February 8, 2011 at 7:50 AM

Hi guys:

I have the same problem with iBooks, it can read pdf's and my ebooks, but no the paided ones from Ibook store.

I tried with the last redsn0w release and with greenpoison. I noted this:

1.- A fresh Ipad install, no jailbreak, everything works fine
2.- Tethered redsn0s jailbreak, cydia not workng (white icon), ibooks with no problems
3.- Greenp0ison for untethered jailbreak, now cydia worked and also ibooks
4.- First cydia run, it asks for the upgrade, ipad rebooted and the books buyed by ibooks never opened again.

My iPad is 3G - 64Gb and the same problem happen with my Iphone 4 - 32 Gb both with 4.2.1 firmware

I hope this could be useful for solve this

Thanks guys

February 8, 2011 at 9:09 PM

I noticed the following problems with my iphone 3gs 4.2.1 after i jb with greenpois0n:

- delete of sms from a single sender not working but deletion of individual sms thread is working
- it's always looking for a cellular network to connect to the internet
- redial not working

Any ideas how to fix his?

February 8, 2011 at 11:58 PM

it worked....KUDOS to the Dev team... I have a skill instead of an apple logo :( ...but anyway thanks.

February 9, 2011 at 2:01 AM

I receive this error ...

1.unable to find gBdevList
2.unable to find fs_mount
3.unable to find fs_unmount
4.unable to find fs_load_file

greenpois0n box says it has completed via the blue and white status bar . I also tried the windows version and it fails as well. I am running a non-jailbroken iphone 4 with 4.2.1 on it . any ideas ?

February 9, 2011 at 5:01 AM

my ipod does not turn on, what I can do?

February 9, 2011 at 9:56 AM

Worked on my 3gs as expected. Will post if there are any defects.

Good job and thank you very much.

February 9, 2011 at 11:06 AM

just recently updated/jailbreak my iphone4 4.2.1 and everytime i plug it to the usb i get this message

"it is potentially dangerous to perform actions while cydia is installing software"

please help...thx

February 9, 2011 at 11:31 PM

When you go from redsn0s jailbreak to the Green0ison, did you have to restore the iPad to fresh install?

February 10, 2011 at 5:01 AM

Does this work with apple tv 2nd gen?

February 10, 2011 at 8:01 AM

Hey guys i have the
unable to find gBdevList
unable to find fs_mount
unable to find fs_unmount
unable to find fs_load_file

error and a second later it disappears and everything seems to be working fine. it goes through the whole process but it doesn't jailbreak it... it returns me to the unactivated home screen and i can only make emergency calls. I have the 3GS on 4.2.1 and bootrom 5.15.04 and bootloader 6.4. does anyone have any ideas qhy it wont work????

February 10, 2011 at 8:01 AM

Click on the windows download link and my computer can't find the page! I can,t download!

February 10, 2011 at 3:37 PM

greenpois0n rc5-4 worked flawlessly on my iPhone 4.
Once the process is complete, just plug your phone into iTune again, it will activate the phone, ask you whether you want to restore as a new phone of from a backup. Then you're good to go.

February 10, 2011 at 5:01 PM

Worked for me, i had tethered jailbreak with redsn0w and this worked straight over the top of it, cheers. Iphone 3GS 16gb

February 10, 2011 at 10:54 PM

I got the same errors like others and when i try to open cydia i go back at my locked screen!!any help?

February 11, 2011 at 12:50 AM

I found that if you hold down the home button until the whole process is finished worked for me (step 6.3 in the instructions).
I have a iphone 3GS running Ver. 4.2.1 (8C148a) Model MC132X.

Tried as per instructions and releasing the home button after 15 sec. several times and failed until I held the home button down until the end

I hope it works for you

February 11, 2011 at 4:33 AM

Am I the only one having issues with bluetooth after the jailbreak? iphone is pairing normally but headset is not working at all. Also the cydia app "Bluetooth" is crashing right after starting.
That all worked perfectly before jailbreak.

wei guo
February 11, 2011 at 3:47 PM

i was running this on my 3gs 4.2.1
first time i saw

unable to find gBdevList
unable to find fs_mount
unable to find fs_unmount
unable to find fs_load_file

then see error to download fireware something.

and then i restart my iphone and connect to a wifi internet.
and then i tried second time,i successfully did it!

February 12, 2011 at 5:52 AM

Sorry about my comment in portuguese.

I just want to thanks all the team that works a lot and work´s hard to find solution and help everyone that make many mistakes with your´s iphone´s.

The program dind´t work at the first time. I needed to make another tutorial and than make de greenpoison again.

So my iphone it´s alive.

Thak you some for everyone

February 12, 2011 at 9:18 PM

It worked nicely in my ipod touch 3g! Great work!

February 13, 2011 at 12:54 AM

When is greenpoison going to fix the gba emulator and other such glitches?

February 14, 2011 at 3:55 AM

i have an ipod touch 4g runing on 4.2.1 & after rebooting it doesnt show the "loader" icon. what do i do ?

February 15, 2011 at 3:50 AM

It's work for IPhone 3GS 16GB New bootrom?

February 17, 2011 at 6:45 AM

Can someone help me? I'm currently jailbroken on a 3GS 4.1 with Limerain. I know I can re jailbreak if I update to 4.2.1 but the other day, my Itunes had an update of 4.2. If I update 4.2, will 4.2.1 show up after that? Please help.

February 21, 2011 at 2:54 PM

do i need to be online when i jailbreak my ipod touch 4th gen?

February 21, 2011 at 4:10 PM

i cannot jailbreak my ipod... the greenpoison said "jailbreak failed :(". someone help me please.... thanks....

February 22, 2011 at 7:00 AM

My tried jailbreaking my 3GS multiple times and every time green pois0n consistently said "failed:(". How do I fix this?

February 24, 2011 at 8:42 AM

has anyone goten a virus when downloading this???

February 24, 2011 at 9:25 PM

Wow!!! At first i did the normal jb from greenpois0n but the cydia didnt work so i used red snow redsn0w 0.9.6 rc8 to do a tethered jb first then greenpois0n, now itz completely working!!!!!!

February 25, 2011 at 10:59 AM

my ipod wont turn on1 it turns on then the apple turns into the skull and sits there forever! what do i do?!?!?!?

February 27, 2011 at 2:44 PM

I've jailbroke my bro-in-law's 3gs new bootroom n my ipod touch 2g..it really works..just want to point out something,it seems that GP will run smoothly without errors if u run it with Windows XP..when i ran it with Windows 7,some errors pops out,like the 'unable to find' thingies..but when i ran it in XP,it works perfectly on the 1st try..so people,this could be a useful tip

February 11, 2013 at 7:32 AM

Hey! I was able to do everything and I was also able to install Cydia. However, whenever I run it, it crashes/ closes/ brings me back to springboard. Can someone help me resolve this problem? I'll appreciate. Thanks!

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