diff --git a/cpu/cc2538/startup-gcc.c b/cpu/cc2538/startup-gcc.c
index c9febb4f6..99a624a7d 100644
--- a/cpu/cc2538/startup-gcc.c
+++ b/cpu/cc2538/startup-gcc.c
@@ -40,12 +40,13 @@
 #include "reg.h"
 #include "flash-cca.h"
 #include "sys-ctrl.h"
-#include "uart.h"
 
 #include <stdint.h>
 /*---------------------------------------------------------------------------*/
 extern int main(void);
 /*---------------------------------------------------------------------------*/
+#define WEAK_ALIAS(x) __attribute__ ((weak, alias(#x)))
+/*---------------------------------------------------------------------------*/
 /* System handlers provided here */
 void reset_handler(void);
 void nmi_handler(void);
@@ -62,6 +63,9 @@ void cc2538_rf_rx_tx_isr(void);
 void cc2538_rf_err_isr(void);
 void udma_isr(void);
 void udma_err_isr(void);
+void usb_isr(void) WEAK_ALIAS(default_handler);
+void uart0_isr(void) WEAK_ALIAS(default_handler);
+void uart1_isr(void) WEAK_ALIAS(default_handler);
 
 /* Boot Loader Backdoor selection */
 #if FLASH_CCA_CONF_BOOTLDR_BACKDOOR
@@ -83,22 +87,6 @@ void udma_err_isr(void);
 #else
 #define FLASH_CCA_BOOTLDR_CFG FLASH_CCA_BOOTLDR_CFG_DISABLE
 #endif
-
-/* Link in the USB ISR only if USB is enabled */
-#if USB_SERIAL_CONF_ENABLE
-void usb_isr(void);
-#else
-#define usb_isr default_handler
-#endif
-
-/* Likewise for the UART[01] ISRs */
-#if UART_CONF_ENABLE
-void uart0_isr(void);
-void uart1_isr(void);
-#else /* UART_CONF_ENABLE */
-#define uart0_isr default_handler
-#define uart1_isr default_handler
-#endif /* UART_CONF_ENABLE */
 /*---------------------------------------------------------------------------*/
 /* Allocate stack space */
 static unsigned long stack[512];