Programming BOOTCFG register: Application not booting up

Hi,

I am using TIVA C 129X Dev board and trying to program BOOTCFG register , to invoke bootloader based on the value of PB4 on power up. After programming the Bootcfg register, i did a full power reset, and the value of BOOTCFG register is showing correctly (read back from CCS).

I loaded the blinky example to board and the LED is blinking. If i press reset or do full power reset, The blinky is not booting up. To check, I tried updating FW using LM flash programmer and its not able to communicate with Board. 

Its working every time when i load it from CCS by pressing the debug option. But when i do a reset its not.. 

What does it mean?

Code is given below:

void progBootCfg_reg()
{



if (( FLASH_BOOTCFG_R & FLASH_BOOTCFG_NW ) != 0 )
{

   // Write the desired boot configuration to the FMD register
   FLASH_FMD_R =0x7FFF30FE ;  // (FLASH_BOOTCFG_PORT_B | FLASH_BOOTCFG_PIN_4 | FLASH_BOOTCFG_POL | FLASH_BOOTCFG_DBG1);

  // Write the address of the register which we wish to commit
  FLASH_FMA_R = 0x75100000;

  // Write to non-volatile register (KEY + COMT bit)
  FLASH_FMC_R = (FLASH_FMC_WRKEY | FLASH_FMC_COMT);//Poll COMT bit in the FMC register until the commit operation is complete

  while((HWREG(FLASH_FMC_R) & FLASH_FMC_COMT))
  {
  }

}

}

Should I configure any other things to get it working?