I finally got it working.
I messaged someone on YouTube asking about it and this is what they had me do:
"I'm not sure what version and baseband your iPhone4 is but I do know that the Gevey should just work right out of the box with any version below 4.3.1 and any baseband below 04.10.01. I was able to use it on version 4.2 with baseband 02.10.04 but my girlfriend accidentally updated it to 4.3.1, 04.10.01. That's where it took me 4 days to figure out.
*First, you're going to need to download the latest redsn0w software and the IPSW that is related to your version. You can easily google them. Say mine is 4.3.1, so I need the file "iPhone3.1_4.3_8F190_Restore.ipsw. You're also going to need to have your iPhone be connected to some kind of internet/wifi access, else it will not work.
*Next, plug your iPhone to your computer and shut off your iPhone completely. Run redsn0w. Click on the "Browse" button and select your IPSW, wherever you saved it. Click next and select "Install Cydia" ONLY. Click next and it will then provide u with steps to get your iPhone into DFU mode. Let redsn0w run its course and it will reboot for you.
*When all is done, connect your iPhone to wifi. Go into your Cydia app and it will start downloading some files. Once it's done, click on "Manage" (on the bottom). Click on "Sources". Afterwards, there should be an option to select "repo666.ultrasn0w.com. If there is no option to select that, then enter it manually. Note that the 0 in sn0w is a number. Click install and confirm and let it run its course. When it's done, there will be a pop-up button that tells u to reboot your phone. Go ahead and reboot your iPhone. Once your iPhone is fully rebooted, shut your iPhone completely off. Insert your Gevey Sim and go through the usual installation process. It may not work on first try but keep repeating the Gevey steps and it will eventually work. You'll know when it starts working is when you turn your Airplane mode on and off and the reception says "Searching...". Just be patient and let it search for reception."
that ended up working!
