As you don't have your original NAND image, you can use your freeBOOT 9199 image to make a new freeBOOT 0.4 image. Follow the xbox360iso tutorial for upgrading to 12611, and use your freeBOOT 9199 image when asked. Rename the image to updflash.bin, place it in the root of a Flash drive, connect it to your Xbox360, then run Flash360 Or boot XeLLous and write the image while keeping your current KV and Config. All Done!