5D MII and 5D MIII firmwares in 1 card

[wshintani]

Hello,

I have a doubt involving two separate firmwares in one card. I have both cameras but would like to use both firmwares in its respective camera but dont know if I can keep them both in one single card and use either depending which camera I choose to use.

Thanks

[a1ex]

Don't do this.

[wshintani]

Don't do this.

so separate cards for each camera?