I used this tool for restoring Leopard board. Download it and configure it to use u-boot for Leopard Board. Much more faster than serial flash utility.
Source and binary: http://www.linux-davinci.info/data/boot/
This is a good information.
I will post this contents in FAQ.
Is it working for the Leopard Board DM365 too? Because when I'm trying to write on the NAND (using my LP365), it says "Write verify failed" and after rebooting, nothing has been changed on the board...