[U-Boot] i have problem with u-boot-2010.03

[nguen duy phuong]

Dear everyone i'm Phuong i living vietnamesepresent, i research chip's atmel (AT91SAM9260) and i want to install u-boot on chip AT91SAM9260 but i have some problem with it, so that i need help from you 
this is my step build u-boot:
step 1: i configure it for chip AT91SAM9260 technical information:   Basetext :21f00000   set At45DB041D 0x1C   Bus with sdram to 16Bitsstep 2: i build it with gcc,toolchain  make 0=/tmp/build distclean  make 0=/tmp/build at91sam9260ek_dataflash_cs1_config  make 0=/tmp/build allstep 3 : i open samba v2.9 in windows   i puts bootstrap v.1.5 in 0x0  i puts u-boot.bin in 8400final: i'm reset my board but i get cksum bad. i don't understand it. can you help me ???
note: i use linux OS(ubuntu 9.04)
 I am looking forward to hear from you soon