All right, here's what happened:
1) I bought a PSP, 2.71 firmware, and an IC1003 Motherboard.
2) I charged the PSP's battery all the way.
3) Then, used the USB cord I bought to connect it to the PC.
4) From there, I followed all the steps in the "Ultimate Downgrading" guide:
"...DarkAlex's 2.71 Downgrader and Download Homebrew Enabler for FW 2.71 using the Link below.
Follow the instructions in the readme file of Homebrew Enabler for 2.71 Rev.C to install HEN-C
Once done, reboot your PSP and run the Homebrew Enabler using the Photo Menu.
Now simply extract the files in the downgrader archive below to your PSP and paste the EBOOT.PBP file of the updater into the PSP/GAME/UPDATE folder.
Now just run the updater using the Game menu!"
5) Went to the game menu, and it said something like "Updater XY.Z" or something like that. It booted up, and in a DOS-like font, started rewriting the flash info after I pressed X agreeing that it MIGHT be bricked.
6) After it had finished copying 100% of the files, it said it would reboot the PSP. I waited 10 minutes, but nothing happened.
7) Reset the power. And it did just what it's doing now; being a brick.
Everything looked fine until the last minute. Ugh.
EDIT: I couldn't tell if HEN C was running or not. Looked like it was, I got the Blue then Green screens.