I just got my first smart phone (iPhone 3g 4.2.1) and wanted to use it on StraightTalk.
I read that in order to unlock the phone for carriers besides AT&T, I had to raise the phone's baseband to the iPad baseband. I was following the instructions on this site, and it said installing the iPad baseband was "currently the only way to unlock 05.14 and 05.15 basebands". That may have changed since then.
That didn't work, and I tried (to no avail) to restore it with iTunes. I ended up stuck with the "Connect USB to iTunes" screen. I looked for help on Reddit, and followed this advice:
Either download the 4.2.1 ispw file for iPhone 3G or locate the ispw file inside your iTunes and place it on your desktop.
Got it (iPhone1,2_4.2.1_8C148_Restore.ipsw). It takes a long time to download, but isn't hard to find.
Now try and get your iPhone into dfu.
I was stuck in the "Connect to iTunes" page, but this guide helped me get into DFU mode (or so I thought)
Once in dfu open the newest version of redsn0w.
Got redsn0w 0.9.14b2 (OSX) from iphone-dev
Once open click extras,then select ispw. Choose the ispw 4.2.1 on your desk top. Now a pop up will state resn0w will use the 4.2.1 for the remainder.
So far so good!
Select back,then jailbreak. Since you are already in dfu it should skip the step where it shows you how to do it. Now this should get you out of recovery.
Since I heard there was no need to upgrade to iPad baseband, I selected "Downgrade from iPad baseband". Apparently I wasn't in DFU mode, since it gave me steps to enter DFU mode... dangit.
Screen flashed white, then said "Downloading Jailbreak Data…", and a lot of terminal readout showed up on the screen. Now a running pineapple showed up with a status bar under it. Now it's stuck on the apple logo screen, and has been for several minutes. After being stuck about 2 hours, I turned it off, tried to turn it on, and got stuck with the apple logo screen.
Also, the person on Reddit said I didn't need to unlock the iPhone to use it with Straight Talk. Is that true? I talked to some Straight Talk people in a store, and they said I couldn't use iPhone with them, and everything I read said I had to unlock it.
So now, I beseech you for your help
The most my phone will do is show an apple logo when it powers on. iTunes doesn't register that it's plugged in. Por favor help; what should I do?
Wow that's a lot. First of all your going to have to restore. Since you installed the iPad Baseband you can only restore using a Custom iPSW. Since you don't have one we're going to have to create one using redsnow. Open redsnow, click extras, and select Custom iPSW. A dialog window should pop up, go to where you have the ORIGINAL iPhone 3G 4.2.1 iPSW and select it. Press ok and It should then create a NO_BB iPSW in the same location as where the original iPSW is. Second step is to enter PWNed DFU mode. Open redsnow again, click extras and select PWNed DFU mode. Follow the onscreen instructions and you should be in PWNed DFU mode. Open iTunes and a message should show stating that your device is in recovery mode. Great now press ok, hold Shift and click Restore. A dialog box should show, go to where the NO_BB iPSW is. Click it and press ok. Your device should now be restoring. Afterwards your device should turn on. Letme when you get here. (ps you should always Select iPSW before using redsnow).
you may try this sir: