To be absolutely honest, I have never seen N900's damaged chip that would "look" damaged (burned, or something) - it looked exactly like before damage. Although, some of them *smelled* as burned.

Otherwise, I'm out of ideas. Something definitely got damaged during repair attempts, but I can't pinpoint it for you (probably, wouldn't be able to pinpoint it even having board in my hands - lack of adequate probing equipment and/or knowledge, if damage isn't obvious).

/Estel