Flashing "over" another tune

[minytrker]

Im pretty sure that most tuners will still flash even if they have been flashed over. They are still locked to the ecm, and they should just flash over the efi live tune... someone correct me if I am wrong?

I dont mess with hand helds very much but I have seen them end up being worthless after I have tuned something and the owner forgot to flash it back to stock first.

[skneeland]

Im pretty sure that most tuners will still flash even if they have been flashed over. They are still locked to the ecm, and they should just flash over the efi live tune... someone correct me if I am wrong?

I havent tried it, but assuming most tuners are locked to the ecm until you go through the "return to stock" motions. Im guessing that once you flash over the box tune with EFI live (or another box tuner perhaps) that the original box tuner wont recognize the software/ecm anymore and remain in limbo.
As i stated, i havent tried this and am only making an educated guess, but why would anyone risk it for a test? short of maybe losing your tuner module & needing to reflash anyway.

[Straight 6]

I did this with a super chip and a smarty once... i had the superchip tune on there and tuned it again with my smarty... the smarty just overrided the superchips and tuned it like it was never there... i couldnt remove the superchips until i set the smarty back to stock and then i could remove the superchips and eventhough my truck was stock the superchip pulled the tune off and was fine i used it on my truck again and a buddies truck with no issuse... maybe i just got lucky or maybe it was just because it was a superchip but if it helps anyone there ya go lol

i can also say that i tuned my truck with my smarty and pulled the smarty tune off with efilive and havent had a issues yet... although u will turn the truck back to stock with the smarty before retuning with efilive