[U-Boot-Users] Booting from serial flash?

Hi everyone, I was wondering if anyone can help me on this matter: does the U-boot support loading solely from serial flash or nand flash (i.e. no other flash is available)? If so, which of the boards support that. I've been digging into the U-Boot files and I found support for compact flash but it exists along with another flash memory, where as I need a bootloader running with only compact flash. Thanks, Hoda