diff --git a/platform/cc2538dk/contiki-conf.h b/platform/cc2538dk/contiki-conf.h
index fca5a3d00..32469b7d9 100644
--- a/platform/cc2538dk/contiki-conf.h
+++ b/platform/cc2538dk/contiki-conf.h
@@ -48,7 +48,16 @@ typedef uint32_t rtimer_clock_t;
 #ifndef FLASH_CCA_CONF_BOOTLDR_BACKDOOR
 #define FLASH_CCA_CONF_BOOTLDR_BACKDOOR	1 /**<Enable the boot loader backdoor */
 #endif
+
+#ifndef FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN
+#define FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN 3 /**< Pin PA_3 (Select button) activates the boot loader */
+#endif
+
+#ifndef FLASH_CCA_CONF_BOOTLDR_BACKDOOR_ACTIVE_HIGH
+#define FLASH_CCA_CONF_BOOTLDR_BACKDOOR_ACTIVE_HIGH 0 /**< A logic low level activates the boot loader */
+#endif
 /** @} */
+
 /*---------------------------------------------------------------------------*/
 /**
  * \name Flash Memory configuration
diff --git a/platform/cc2538dk/startup-gcc.c b/platform/cc2538dk/startup-gcc.c
index b47ae39ed..8647fd638 100644
--- a/platform/cc2538dk/startup-gcc.c
+++ b/platform/cc2538dk/startup-gcc.c
@@ -65,9 +65,21 @@ void udma_err_isr(void);
 
 /* Boot Loader Backdoor selection */
 #if FLASH_CCA_CONF_BOOTLDR_BACKDOOR
-/* Backdoor enabled, on PA_3 (Select button) */
-#define FLASH_CCA_BOOTLDR_CFG (FLASH_CCA_BOOTLDR_CFG_ENABLE \
-  | ((3 << FLASH_CCA_BOOTLDR_CFG_PORT_A_PIN_S) & FLASH_CCA_BOOTLDR_CFG_PORT_A_PIN_M))
+/* Backdoor enabled */
+
+#if FLASH_CCA_CONF_BOOTLDR_BACKDOOR_ACTIVE_HIGH
+#define FLASH_CCA_BOOTLDR_CFG_ACTIVE_LEVEL FLASH_CCA_BOOTLDR_CFG_ACTIVE_HIGH
+#else
+#define FLASH_CCA_BOOTLDR_CFG_ACTIVE_LEVEL 0
+#endif
+
+#if ( (FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN < 0) || (FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN > 7) )
+#error Invalid boot loader backdoor pin. Please set FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN between 0 and 7 (indicating PA0 - PA7).
+#endif
+
+#define FLASH_CCA_BOOTLDR_CFG ( FLASH_CCA_BOOTLDR_CFG_ENABLE \
+  | FLASH_CCA_BOOTLDR_CFG_ACTIVE_LEVEL \
+  | (FLASH_CCA_CONF_BOOTLDR_BACKDOOR_PORT_A_PIN << FLASH_CCA_BOOTLDR_CFG_PORT_A_PIN_S) )
 #else
 #define FLASH_CCA_BOOTLDR_CFG FLASH_CCA_BOOTLDR_CFG_DISABLE
 #endif