Using other firmwares on flash carts?

This might sound like the stupidest thing ever (and it might be the wrong section too), but I have to ask. How can I put other firmwares on my flash cart?Now, I'm using a DSTT, but this apply to a variety of things. I know you can run things like ysmenu on flash carts, but what if I wanted to use..say... The cycloDS firmware on my DSTT? How could this be done? Or is it as easy as loading it up on the SD card? Or, could you run it as a .NDS file, sort of like what you do with YSMenu?I've always wondered about this, so I'd appreciate any logical feedback. 8)8)

Not really possible as far as I know, sorry. At least, for some to work it would take a lot of hacking, and some cards are so physically different it would be pretty much impossible.