diff --git a/tools/fit_image.c b/tools/fit_image.c
index 3ecc88f..2c8d92f 100644
--- a/tools/fit_image.c
+++ b/tools/fit_image.c
@@ -517,7 +517,7 @@
 		}
 	}
 
-	munmap(fdt, sbuf.st_size);
+	munmap(old_fdt, sbuf.st_size);
 	close(fd);
 
 	/* Pack the FDT and place the data after it */