I'm guessing it's on USB 1.0? I had to also search out a VERY old USB drive for modding an original Xbox a while back, and the internet go-to was these surf-board USB drives believe it or not. I think they were branded "SurfDrive", something about them made it work with the very picky older hardware, must have gotten the company rich for the wrong reasons. Might want to give it a go.

Probably just easier to buy the pre-loaded thing though if it's around the same amount. (The drives are like $12-$13 plus shipping, I believe, I just looked.)