Electronic – Arduino bootloading

Yes, you can reprogram the chip. I did the same when I upgraded my Arduino from a 168 to a 328 two weeks ago. The chip works great in another application.

Take note, of course, that you may need to change fuses depending on what kind of board you had and what kind of board you are moving it to. The most common, I would imagine (and the ones I had to reset) dealt with changing to the internal oscillator and setting dividers instead of using an external crystal. There is no comprehensive list of fuse changes, though, because it depends on what kind of circuit you're moving the chip to. YMMV.

--Edit-- As JohnC said, yes, reprogramming of fuses should be done BEFORE you remove it from the Arduino. Since the Arduino is fused to use an external oscillator, the chip will not do a darn thing if placed on a board without an oscillator.

As of now, you can. Actually, apparently the big problem with the Uno is the auto reset - if you put about a 120 ohm resistor from reset to 5 V on the Uno then it'll work.

Load the ISP sketch, disable the auto reset with the resistor, and then follow the normal directions.

(I just burned three chips last week from my Uno - so I know this works.)