Hey man, it sucks you tried switching the hard drives. I've been combing forums for info on whether or not PSJailbreak is releasing a workaround that will allow gamers to run the exploit on 3.42 an newer firmwares, and it seems that most of the results I when I use "3.41" in the search is a now well known...infamous, I guess...glitch in the software that causes it to brick if you try changing the internal hard drive...with firmware v3.41 installed, of course.
You've probably found this out by now, and because I read it early enough to keep away from hard drive upgrades, I haven't had much incentive to read past the into. I believe there is a "fix"...I just on't know if it involves "upgrading" to the exploit-blocking firmware version 3.42.
Again, you've probably figured this out and I know I haven't been very helpful but I on't have the time to read up and you sound smart enough to figure it out yourself...just google 3.41 HDD/hard drive brick or something.
Good Luck man.