The document DM6467_Boot_Loader_UserGuide.pdf found in PSP_02_00_00_140\board_utilities\dm646x\bootloader\docs contains a table describing the different boot modes. The table includes a column for gem_secure_en, but gem_secure_en is not mentioned anywhere else in the document. Also, I cannot find gem_secure_en in the DM6467 datasheet. How does gem_secure_en get set to 0 or 1?