Quoted from metallik:If it's like JJP's ISO update, the card may need to be configured to be bootable. Still, a card that updates one game should work on others, unless CGC has deliberately configured it to erase the update from the card upon completion as some form of copy protection. OTOH it may also create a flag file on the card to show an update has been run, in case people leave the card installed in the game by mistake.
there are SD cards with an write protect switch on them. As for booting does it boot from the card or does the hardware just look for files on a card at power up.