iPhone Stuck at DFU Mode

Hey friends, I need a help here.

These days, my iPhone's 4 GPS has gone, it was able to get location only by triangulation/wifi (blue dot was not pulsating in Maps app). After so many restores and hours with the phone in open places trying to find satellites signal, I realized it was a hardware problem. So, I get my courage and did the "oven trick" (put the iPhone's PCB (motherboard) in the oven for 7 minutes at 385F. This can fix possible solder joints). Bingo! GPS alive after months dead and iPhone workin' fine.

After a month without problem, the gadget starts to show the famous "white screen of death" (WSO) after the phone went to sleep state (screen became white when I pressed "power" or "home" button to wake it up). So, after restores, disassemblings and contacts cleans, I had the "great" idea to put it back in the oven (God knows the oven could fix this issue too...). Bad idea, now the iPhone is stuck in DFU mode. I tried to restore and didn't work, I keep gettin' "error 1600". Actually, iTunes shows the "preparing iPhone to restore" message (I got shsh saved since 4.1, so, I used Tinyumbrella), showing the server accepted the phone's request, but the restoration stops there. As I need the unlock (I live in Brazil), I can't directly update the firmware. I tried to update to a custom Sn0wbreeze current firmware (4.3.3) too, but iTunes shows the same error, even if I use iReb or Redsn0w to put it at pwned dfu mode.

So, the point is... did I brick my iPhone forever? I tried iRecovey too with no success (it says something like "invalid parameter"). Does somebody got any different idea? Even it involves complety disassemble the iPhone, I'll try it!

Thanks in advance!

It's been a while since the last time I post here! Well, sorry to say that guys, but the only solution I found was to change my phone to another one at Apple Store. I tried everything avaliable on internet, and nothing worked. But in my case, after some research, I discovered it was a hardware fault (more specific at the flash memory, the "oven trick" (as I said in the original post) burned the solder joints, making it unstable for a while and finally culminating in a unplugging of the flash memory from the mainboard). But my case was different from yours, there's an oven in the halfway that bricked the phone. But, if the problem persist even a restore, there are strong clues that's a hardware fault. So, don't worry your head too much: go to a store and change your phone!