I am trying to flash my DM368's NAND using TI's flashing utility (sfh_DM36x.exe) using UART.  I've tried it on both Linux and Windows.  Whenever I do I get the following error message:

Target: Writing UBL to NAND flash

Target: Unprotecting blocks 0x00000001 through 0x00000018.

Target: NAND is write protected!

Target: Writing failed! Starting UART boot...

Target: BOOTUBL

Obviously the NAND isn't being unprotected.  Any tips on how to flash the NAND via UART?  Here's an example command I'm using in Windows:

e:\Temp\board_flash>sfh_DM36x -nandflash -p COM3 UBL_DM36x_NAND.bin u-boot-dm368-evm.bin