CC2640R2F: Bootloader mode GPIO setting.

Part Number: CC2640R2F

Hi 

I  have a simple question about GPIO for bootloader backdoor.

Per this table, do we MUST use DIO 0/1 for UART on cc2640R2F wcsp ?

Per the code, this pin is all GPIO is available? Like DIO4.

#ifndef SET_CCFG_BL_CONFIG_BL_PIN_NUMBER
#define SET_CCFG_BL_CONFIG_BL_PIN_NUMBER 0xFF // DIO number for boot loader backdoor
#endif

Thank you very much.