Rymez2k from the Xboxhacker forums has successfully transfered a game save from his Xbox to his Xbox 360 and the save was functional. The way he went about doing it, however, was rather complicated:

I have succesfully got a FIFA 2004 save loaded on my 360.
Basically the steps I took are as follows:

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 UDATA4541003b and TDATA4541003b 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 CompatibilityXbox1

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.

This procedure might help people who want to transfer saves over to their 360.

Also I won't supply any images/files so please don't ask.

Ensure you know what you are doing, I take no responsiblity if you trash your pc/360 drive.