It starts whatever is in the Slot 2 (Gameboy Advance Slot) on the DS. If there was say, a Gameboy Advance game in Slot 2 then it just plays the game (Just like "Start GBA Game" in the normal DS menu does) but it can have a custom border around the screen, which can be edited in the /system folder on your MicroSD/TF card (it's called gbaframe.bmp). It can also load some DS Flash Carts. Just remember that Roms are illegal!
An R4DS is a Slot-1 "flash cart" for the Nintendo DS. A Flash Cart is a device that is used to allows you to play homebrew and games for that system. There are Slot-1 and Slot-2 Flash Carts. Most DS flash carts require a MicroSD memory card. Be careful when you buy a DS flash cart, because some can and some can not read MicroSDHC cards. All Memory cards with 4GB or higher memory are SDHC. There are alternatives to the R4DS, such as the DSTT, Acekard 2, and TopToy.
You cant, R4ds doesnt supply ds download play. You just need to take the r4ds out of the slot and go into ds download play manually.
It is possible, but you need the ez flash 3in1 expansion pack that goes in the gba slot along with extra software
huh? the R4DS is for the Nintendo DS.
no, but there is no need to, the R4DS has a built in Action Replay.
The R4DS cartridge is to be inserted into the DS's Slot 1, as a regular Game Card would be inserted, the label facing away from the console.
No it is illegal
Yes the r4ds boots up game boy games into ds mode.
the question is a bit vague: The best model for R4DS: The original R4DS (not pro, not ultra, not SDHC, not R4i etc.) The best kernel version: v1.18 (Released 24th April 2008) www.r4ds.cn
Slot 1 is the slot at the top of the DS, for DS games. Slot 2 is the slot at the bottom of the DS, for GBA cartridges.
no it is not illegal
no