It looks like someone has made their Xbox FIFA 2004 save game work on their Xbox 360. It is a long and very involved process, so it is not for the faint of heart.
The instructions in their “complete” form are here for you to look at, but I suggest going over to the orignal article at XboxHacker.net, and hitting up the forums before you attempt this.
Loaded original FIFA 2004 Game in my xbox 1
Created a profile/save.
Went into Edit Profile and changed the Profile Name, First Name, Last Name, And MyTeam.
FTPed across the following directories on UDATA\4541003b and TDATA\4541003b to a directory on my PC.
Then loaded up linux PC (Which has the new FATX support.)
dd out the second partition 0x130EB0000 to the end to a file (Approx 14Gb)
dd if=/dev/sda of=Partition1.dd skip=4995776 bs=1024
then mounted this image using the loopback device
mount Partition1.dd /mnt/xbox -t fatx -o loop
Next I copied the UDATA and TDATA direcories over the current ones which are at \Compatibility\Xbox1
Unmounted the image and dd the image back to the hard drive.
dd if=Partition1.dd of=/dev/sda seek=4995776 bs=1024
Then loaded up FIFA on my 360 and I could load the profile I had saved earlier on my original xbox.
I intend to test this with Rocky Legends aswell as that is the only other xbox 1 game I have at the present moment.
Notes. 4541003b is the game code. These codes are easy to work out.