It definitely won't work on your phone. Turning it into a brick? I'd DEFINITELY have a backup PB00IMG.ZIP on another SD card ready for you to VOL DOWN + POWER when you mess up your phone.
If your phone won't start up with that (which it won't), you'll have to already have a backup plan. if you're on 1.5, you might be SOL, and the bootloader may upgrade (highly doubtful it'll even get this far), OR it may do nothing and tell you no (highly probable), and if it DOES actually upgrade something (which would be a miraculous event), you'd need the Eris 2.1 PB00IMG.ZIP on another SD card ready to go, and not a 1.5 image (or hard reset).
Assuming that this does nothing, which is what I'm assuming, you won't brick your phone, and you'll just start it up normally next time without trouble.
if you get problems, I'd a) try a NORMAL hard reset (hold call + end at same time while off, choose recovery), and if that's a fail, you'll, once again, need a PB00IMG.ZIP like the 2.1 Eris version going around, on a microSD card, that you can put in your phone, and VOL DOWN + END with.
Good luck. I wouldn't try it. But good luck.
