[U-Boot-Users] help about u-boot on lubbock

I have just checkouted the u-boot source code from CVS, and: (use arm-linux-gcc 2.95.3) make lubbock_config make then I use JFlash(windows) to install u-boot.bin in my lubbock(pxa250) board, and I use the HyperTerminal as the console tools for inter-action. after power on, I can get the prompt, but if I try to copy RAM data to Flash like: cp 0xa0008000 0x04000000 1024 u-boot complain that flash not erased, but even I use erase bank 2 to erase the whole bank flash, when I use md 0x04000000 to see the value in flash bank 2, I found that the value is same as old, How can I solve this problem, please help me. Thanks. Hongda Zhao