diff --git a/fusee/fusee-secondary/src/fs_dev.c b/fusee/fusee-secondary/src/fs_dev.c
index 79f8a69..dc566f4 100644
--- a/fusee/fusee-secondary/src/fs_dev.c
+++ b/fusee/fusee-secondary/src/fs_dev.c
@@ -385,7 +385,7 @@
             return -1;
     }
 
-    if(pos < 0 && off < -pos) {
+    if(pos < 0 && pos + off < 0) {
         /* don't allow seek to before the beginning of the file */
         r->_errno = EINVAL;
         return -1;