diff --git a/flash.h b/flash.h
index 59c6c47..e3cd49e 100644
--- a/flash.h
+++ b/flash.h
@@ -34,7 +34,7 @@
 #define __DARWIN__
 #endif
 
-#if defined(__FreeBSD__)
+#if defined(__FreeBSD__) || defined(__DragonFly__)
   #include <machine/cpufunc.h>
   #define off64_t off_t
   #define lseek64 lseek