I know several people who bricked, claimed a system update bricked them and got the 3DS' fixed free of charge.
it was 5.0.0-11 was causing bricks when it initially came out. or at least partial updates (left old NATIVE_FIRM). 5.1.0-11 fixed this.Until an influx of i bricked during an update bla blah takes place. Which is what put gamestop and Microsoft on alert many years ago during a ban wave.