Can a modded original Xbox play downloaded Xbox 360 games?

To put it bluntly, NO. The Hardware Spec for the Xbox is older than the Xbox 360, so Games built to utilise the 360's hardware would make it impossible for forwards-compatability, it's been hard enough for MS to allow the 360 to be backwards-compatable :).

Before anyone tells you no, let me say something.

I have an original modded one too. I got a BIOS from the bins that was supposedly allowing the use of 360 games.

Now, the 1st Call of Duty game demo for the 360 COULD be played on the Xbox with that BIOS. However, it's the only one in my knowledge.

I think it's possible, I really do. But the dev teams have stopped working on the original, as it's now an antiquity.

What?! No. Of course not. No original XBOX, no matter how modded, can play 360 games.

the different answerers do no longer understand. >.> of course, in case you have a modded Xbox 360, it may nevertheless play popular, un-burned Xbox 360 (a.ok.a. retail) video games. the sole ingredient flashing your 360 does is making it waiting to additionally understand your burned discs. ;)

u can only play them if you download them from the marketplace