Hi zhiwei.li,
one simple appoach could be to locate specific objects or parts of it explicitly to the BOARD_FLASH section.
This can be done in the linker file 'Application\Project\GCC\LPCXpresso54628.ld'.
Fore example to locate all the code of Core.c and all read only data of BrickGame.c to BOARD_FLASH section modify LPCXpresso54628.ld as follows:
...
.text_Flash2 : ALIGN(4)
{
FILL(0xff)
*Core.o(.text*)
*BrickGame.o(.rodata*)
*(.text_Flash2*) /* for compatibility with previous releases */
*(.text_BOARD_FLASH*) /* for compatibility with previous releases */
*(.text.$Flash2*)
*(.text.$BOARD_FLASH*)
*(.rodata.$Flash2*)
*(.rodata.$BOARD_FLASH*)
} > BOARD_FLASH
/* MAIN TEXT SECTION */
...