diff --git a/firmware/hackrf_usb/usb_bulk_buffer.h b/firmware/hackrf_usb/usb_bulk_buffer.h
index 6e120714..25e710ee 100644
--- a/firmware/hackrf_usb/usb_bulk_buffer.h
+++ b/firmware/hackrf_usb/usb_bulk_buffer.h
@@ -26,10 +26,13 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#define USB_BULK_BUFFER_SIZE 0x8000
+#define USB_BULK_BUFFER_MASK 0x7FFF
+
 /* Address of usb_bulk_buffer is set in ldscripts. If you change the name of this
  * variable, it won't be where it needs to be in the processor's address space,
  * unless you also adjust the ldscripts.
  */
-extern uint8_t usb_bulk_buffer[32768];
+extern uint8_t usb_bulk_buffer[USB_BULK_BUFFER_SIZE];
 
 #endif/*__USB_BULK_BUFFER_H__*/