Boot it via the Eject button.
If a blue screen comes up, it's a JTAG/RGH (which I wouldn't remove the hack)
If the dash comes up, it's a flashed drive.
Which is reversible (really easy)
If the dash comes up, it's a flashed drive.
By booting you mean I turn it off then on by pressing eject button?
Well if there is a second NAND it may boot the one with the stock dash.