I recently purchased an iphone 3g online (unlocked and jailbroken) I updated to os 4.2.1. and found my phone not unlocked or jailborken any more. I was able to jailbreak my phone and followed the steps to unlock. My phone showed no carrier or network. I placed my sim card in the phone (Cincinnati Bell) and it just kept looking for service. Any help would be appreciatted.

Thanks.

This is a common problem and the solution is easy to find via search. There was absolutely no reason to create a new thread.

The proper solution would have been to not update (you don't update unofficially unlocked iPhones without taking precautions to keep the unlock)

There is no unlock for the baseband that shipped with iOS 4.1

Because you have an iPhone 3G - there is a tiny chance you can downgrade the baseband. Generally there isn't any way to downgrade the baseband back to one that can be unlocked.

First try Fuzzyband Downgrader from Cydia - it will either work (and downgrade your baseband) or do nothing. It won't make things worse.

Otherwise, the only solution you have is to update your baseband to 06.15.00 version. This baseband version has never shipped on an iPhone. It was designed for the iPad. This means that not everything works (gps on iOS 4.2.1 in particular). However it can be unlocked by ultrasn0w. Read the following link very carefully (and then read it again) before you even attempt this.

http://blog.iphone-dev.org/post/1718.../ultra-recycle

Also read this http://www.hackint0sh.org/f204/196391.htm before you attempt the baseband update.

I get a problem with my Iphone 3G . I upgraded my iphone from OS Version 3.0 to 4.2 via Itunes automatic update. After upgrading it, my Iphone stuck, showed Itunes Logo with USB connect. After researching the way to solve it, i tried jailbreak my iphone via Redsn0w 0.9.7b4 . I tried choosing firmware 4.1 , it failed, then tried 4.0 , it also failed, then i tried 4.2 , it was succeed . i choose ipad baseband so that i could unlock it. after seeing my home screen i downloaded ultrasn0w from cydia, and it successfully unlocked.I checked my baseband and it showed me 6.15.00. Everything just fine , i downloaded lot of stuff , used lot of apps but finally when i want to make a call...

this is the problem
when i want to make a call, i cannot find Phone applications, even when i try to call via Contacts, i just can touch the contact name and number without being given any respond

i cannot make a call, check my balance

help me

fyi , i still can receive a call and sms,
in desperate way, when i got a call, i try to make a call by hold that call, but there was nothing happened
i really really want to get my keypad, my iphone's ability to call number back

i have also tried to use Fuzzyband, in fuzzyband it showed the bootloader 5.8 , which i assumed that bootloader is the description of my iphone's bootloader, am i right?

after using Fuzzyband, when i downgraded my iphone from 6.15.00. into 5.1x.xx (i forgot), then it was loading for a while, but then my iphone reboot and show the dim screen, my iphone lost its GSM Signal and the worse, lose WIFI signal too,
then i directly jailbreak it again with my previous step which was succeed before, then it went normal again, but still cannot make/dial a call

Originally Posted by hriccoandrean

i have also tried to use Fuzzyband, in fuzzyband it showed the bootloader 5.8 , which i assumed that bootloader is the description of my iphone's bootloader, am i right?

after using Fuzzyband, when i downgraded my iphone from 6.15.00. into 5.1x.xx (i forgot), then it was loading for a while, but then my iphone reboot and show the dim screen, my iphone lost its GSM Signal and the worse, lose WIFI signal too,
then i directly jailbreak it again with my previous step which was succeed before, then it went normal again, but still cannot make/dial a call

What iOS version and baseband version are you running now? TinyUmbrella can tell you this.

How did you jailbreak it? Redsn0w?

You are very lucky that fuzzyband works for you.

Originally Posted by Olethros

You are very lucky that fuzzyband works for you.

hum .... i believe current version of fuzzyband in Cydia does not include the 6.15.00 certs for downgrade ...
I recalled the last update for fuzzyband is to downgrade from 5.xx.xx but not from 6.15.00.
Do you need the cert to be in there for downgrade though?

Originally Posted by dtube

hum .... i believe current version of fuzzyband in Cydia does not include the 6.15.00 certs for downgrade ...
I recalled the last update for fuzzyband is to downgrade from 5.xx.xx but not from 6.15.00.
Do you need the cert to be in there for downgrade though?

Good point, it appears that it doesn't (yet) support any baseband higher than 5.14.02

you do need the certs to downgrade. It's not a big deal to extract these from the iPad IPSW.

Originally Posted by dtube

hum .... i believe current version of fuzzyband in Cydia does not include the 6.15.00 certs for downgrade ...
I recalled the last update for fuzzyband is to downgrade from 5.xx.xx but not from 6.15.00.
Do you need the cert to be in there for downgrade though?

yes, i downloaded the certificate first , i followed the steps to do downgrade from ipad baseband article using Fuzzyband which has been published on December 31, 2010 (i am so sorry, i miss that link in my history). The link provided with link to download the certificate, and i copied the certificate using DiskAid (manually) into Application --> Fuzzyband.app

Originally Posted by Olethros

Good point, it appears that it doesn't (yet) support any baseband higher than 5.14.02

you do need the certs to downgrade. It's not a big deal to extract these from the iPad IPSW.

Yes after copying the certificate 6.15 into Fuzzyband.app, i ran it and it showed me kind of these informations (not really the same one, but looked like this)

Bootloader
5.08

Baseband
6.15.00

Downgrade
5.1x.xx

(i forgot the version, i just thought, whatever the version, at least the baseband starts from 5 would be great to heal my iphone's call feature, but i know that was wrong)

Ready to downgrade?

then i click ready, but like i said, it was loading for while, it did not show the message " I Haz Downgraded" or any succeed notification, it just loaded and suddenly reboot with dim display

after that frightening moment, i directly repeated jailbreak with redsn0w 0.9.7b4 with firmware 4.2.1 and give the "normal" iphone back (but still without Make A Call ability)

(before jailbreaking using firmware 4.2.1, i tried jailbreaking twice first. First, with 4.1 , then my iphone was on but showed dim effect, blink-blink light everytime i touched it and then i jailbreak it wity firmware 4.0, but it was failed too , and showed the same thing. I just think it is because after you upgrade your iOS into 4.2.1 you cannot go back, and after that i read lot of articles that showed the same thing, you cannot downgrade your firmware at least using custom firmware via pwnage tool , i have not tried it yet, too scare to make my iphone messier >_<)

Tiny Umbrella shows me that my iOS version is 4.2.1 and my baseband is 6.15.00

Please give me some enlightments

is the phone showing correct IMEI #, wifi and bluetooth working ?

Originally Posted by dtube

is the phone showing correct IMEI #, wifi and bluetooth working ?

sorry, i do not really know with what i should match the correctness of IMEI with?
Are IMEI in Tiny Umbrella same with IMEI in my iPhone? is that what you mean? if yes, i can answer they are same.

Wi Fi is working with iOS 4.2.1 baseband 6.15.00,

Additional info:
when i downgraded with fuzzyband, The Wi Fi signal lost, even Wi Fi setting could not be change (block, with grey freeze color), the GSM signal lost, and information which was contained in "About" menu lost too, so when i downgraded i could not know in what baseband I was and in what firmware. At that time, tiny umbrella also could not provided the information about firmware and baseband.

And about bluetooth, i have not tried to test with it, because that feature is not really being my concern as long i am using it rarely. The main thing i need is how to make a call