diff --git a/nvttest/nvttest.c b/nvttest/nvttest.c
index 89c98d7..d5baf16 100644
--- a/nvttest/nvttest.c
+++ b/nvttest/nvttest.c
@@ -59,6 +59,12 @@ static void    *_worker(void *arg)
         }
 
         {
+            int             i, len;
+            char            buf[1024];
+
+            for (i = 0; i < (int)sizeof(buf); i++)
+                buf[i] = '0' + i % 10;
+
             fd = open(dev, O_RDWR);
             if (fd < 0)
             {
@@ -66,11 +72,20 @@ static void    *_worker(void *arg)
                 break;
             }
 
-            nw = dprintf(fd, "Hallo\n");
-            if (nw <= 0)
+            for (i = 0; i < 10; i++)
             {
-                printf("write failed: %m\n");
-                break;
+                len = rand() & 0xff;
+                nw = write(fd, buf, len);
+                if (nw < 0)
+                {
+                    printf("write failed: %m\n");
+                    break;
+                }
+                if (nw < len)
+                {
+                    printf("write short: %u/%u\n", nw, len);
+                    break;
+                }
             }
             close(fd);
         }