Hey all, I recently updated to 4.2.1, and everything went well (after a fashion).
I finally got off the connect to iTunes screen (took a long time to find the right SIM card) and now that I'm at the springboard, I can't unlock my phone. No matter how I jailbreak the phone, I can't seem to get a Cydia icon. I searched and deleted a file somewhere in the filesystem but that didn't help. I was wondering if anyone has any other suggestions.
Restore and do it over. But you could tell me what device you have and what jailbreak methods you've tried, then I can be more specific on my instructions.
I have an iPhone 3Gs, 4.2.1 firmware, 6.15 baseband. I've tried greenpois0n, and limera1n. Both said they completed successfully. I know there is an option in redsn0w to just install cydia, but for some reason it won't accept the ipsw file that it would accept just yesterday, so I can't get that far.
Limera1n and greenpois0n don't work on 4.2.1. Redsn0w and PwnageTool are the only ones that work on 4.2.1. I suggest you restore and do it again with Redsn0w. And make sure you have Redsn0w 0.9.6b6 for the latest version. Try getting your 4.2.1 fw from felixbruns.de, those firmwares usually work right on redsn0w.
Judging by what you've got in your "Device" entry, I'm guessing we're talking about a 3GS here that's already been restored to a PwnageTool-made custom 4.2.1 firmware to bypass the Recovery mode screen with the 06.15.00 baseband.
Try just running redsn0w (pointed to the stock IPSW) first with "Install Cydia" option, if that doesn't work, then re-restore to your custom firmware from pwned DFU and try redsn0w (again pointed to the stock IPSW) "Install Cydia" only again.