[U-Boot] U-boot as a mass storage device and DFU support

Dear all,

Could anyone kindly tell me if u-boot supports itself as a mass storage device?

Or if u-boot main stream support the a protocol so call USB DFU(Universal Serial Bus Device Firmware Upgrade)? I have first seen this on openmoko.org and seems they use u-boot as well. However, when I look at the newest u-boot (1.3.4). It seems no code is about it. I don't know if I have overlooked something.

Thanks.

BR, Jacky