Sync to disk after finished write.

brcm_fw_tool/image-ubi.c

@@ -400,6 +400,7 @@ static int ubi_write_volume(int volId, const char *srcPath)
 		}
 	}
 
+	if(res == 0) res = fdatasync(dstFd);
 
 out:
 	if(srcFd != -1) close(srcFd);