Part Number:TMS320C6678

Tool/software: TI-RTOS

I've got a c6678 le rev 3B dev board and I'm using CCS version 7.1.0.00016 with PDK 2.0.5

I want to burn a boot program into flash;the NAND flash to be specific,

The boot program at the moment is rudimentary-small enough to fit in the L2 memory of core0 and all it does is spit out text to the serial debug.

If I load this .out program into core 0 in the debugger over the ice it works OK and I see the debug.

When I follow the procedures set out in 

Processor SDK RTOS BOOT C66x document

http://processors.wiki.ti.com/index.php/Processor_SDK_RTOS_BOOT_C66x 

all appears to be good in that the NAND writer program reports that it has written and verified the flash update

but when I boot from the NAND flash it hasn't worked.

Any ideas as to why this NAND update is problematic and the writer has not worked when it says it has written and verified the update?

Jack