Downgrade iPhone 4 6.1.3 to 6.1.2 for untethered jailbreak?

Just wondering if it's possible to downgrade my iPhone 4 from the current 6.1.3 firmware to 6.1.2 so I can perform an untethered jailbreak?

I purchased my device already updated to 6.1.3 and I've been waiting 2 months for an official untethered but it hasn't arrived (and probably won't be arriving until IOS 7 so Apple doesn't patch any 6.1.3 exploits in the next update).

What's wrong with this iPhone 4?

My friend sold me an iPhone a few days ago.
It was in good condition. The first two days it worked great. Battery held up, no signs of jailbreaking, normal apps bought on iTunes. I logged him off his account on iTunes and I logged into mine. I downloaded a few apps and played for while. I charged it the next day and I played again. Now today, I took it to school. I was showing my buddies a funny video I had that I installed via iTunes on my computer. I proceeded to do my classwork and as soon as I left the class, I clicked the home button to go onto the lock screen. Blank.Nothing. Just a black screen. I thought it somehow discharged (I left it charging so I don't see how this was possible). My friend had iPod usb cable, so he lets me use it to charge it. All I see is the Apple logo, as if it were rebooting. Kept doing this for a long time. I unplugged it and took it home after. I tried to reset it now, hard reset and putting it in DFU mode (it worked for a bit since it changed the screen to the "Connect to iTunes" image.

Now what do I do? Any tips? Different methods of resetting I might have missed?

Added (1). Edit: I'm trying as I type this. It's starting to respond to the DFU mode but now it says that there was an error in downloading the file onto the iPhone, please try again. This has happened 3 times so far.

Should I switch from Verizon to T-Mobile?

I'm currently on Verizon, and have an iPhone 4, but i would really want to switch to the Lumia 925on T- Mobile. I really like the Lumia 925, because of its small borders, and nice aluminium frame. It is just a awesome phone. I do not like the lumia 928, because because of a lot of reasons, but mostly because it doesn't look good, and it looks a little cheap. So tell me would it be worth it to switch because of this phone? Thanks

P.S. No I Do Not Want To Switch To Android

My jvc unit won't connect to my iPhone 5 immediately?

I bought a jvc unit and it won't connect to my iPhone immediately, it takes 3-5 minutes on its own but it will connect right away if I go to settings on my phone and connect to it that way.
When I'm in my moms BMW her Bluetooth connects right away no problem, as soon as I step in the car.

What can I do to fix this?

Lifeproof iPhone 5 case

I ordered one off of ebay in acqua: http://www.ebay.com/...1439.l2648

I can't tell if it's a fake or not. I needed it by Saturday or Sunday and didn't even think about going to walmart. Should I go to walmart and buy it, and when this one comes just return it? Or should I wait? I'm going on a trip Sunday, so I need it before hand! Please tell me if its fake or not, thanks!

How to use apple earbuds with mic on pc?

I have a pair of apple earbuds with a microphone and the remote. They are tested, and work on my iPhone. But when i plug it into my pc, Reaklet Audio Manager asks what thing i just plugged in. I choose mic in, but when i test it on steam, it doesn't work. But the funny thing is, the real earbud (where you put in your ear) acts as a microphone. So when i'm testing to see if it works, i don't speak into the remote, but into the earbud. How can i fix this so that i can use the remote part of the earbuds. I need this quick as I have a meeting soon, and i need a working microphone. I also have the latest computer, as i just built this one.

New hard drive for asus laptop?

I recently damaged my laptop hard drive, when I had dropped my iphone and Lifeproof case on the right side of my mousepad. My computer does not recognize it anymore, and when I start it up, instead od hearing a constant whir like it should it is a disrupted whir. If it had a visual, it would be this:
Normal:___…
Mine:_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

I think it is damaged and i'm told not to open it (the hard drive little box itself) so I need to know which hard drive to buy. The laptop is an ASUS laptop pc with AMD e2-18000 processor. Please help me, this is urgent. I'm using my brother's computer right now.

Can I possibly use my iPhone 5 outside the US if it's contract-free?

Well, I was thinking about getting an iPhone 5 contract-free because I don't feel like paying $109.99 per month since I only earn about $300 a month. So I'm just saving my money up for it. So here's the question, Will I be able to take the phone to other countries? And what else does it do? (the features of Contract-free) Please answer! Thanks!

Added (1). Oh, by the way, I was thinking of using T-Mobile, so yeah.