diff --git a/src/main.zig b/src/main.zig
index afaebeb..6542de6 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -19,6 +19,10 @@ pub fn main() void {
 
     // const alloc = arena.allocator();
 
+    std.fs.cwd().access(hef_file, .{ }) catch |e| {
+        std.debug.panic("Could not open hef file! '{any}'", .{ e });
+    };
+
     var status: hlo.hailo_status = undefined;
     var vdevice      : hlo.hailo_vdevice = undefined;
     var hef          : hlo.hailo_hef = undefined;
@@ -30,7 +34,6 @@ pub fn main() void {
     const input_vstreams         : [max_edge_layers]hlo.hailo_input_vstream = undefined;
     var input_vstream_size       : usize = max_edge_layers;
     var output_vstream_size      : usize = max_edge_layers;
-    var activated_network_group: hlo.hailo_activated_network_group = undefined;
 
 
     status = hlo.hailo_create_vdevice(null, &vdevice);
@@ -55,19 +58,16 @@ pub fn main() void {
 
     assert(input_vstream_size <= max_edge_layers);
 
-    status = hlo.hailo_create_input_vstreams(network_group, @constCast(&input_vstream_params), input_vstream_size, input_vstreams);
+    status = hlo.hailo_create_input_vstreams(network_group, @constCast(&input_vstream_params), input_vstream_size, @constCast(&input_vstreams));
     assert(status == hlo.HAILO_SUCCESS);
 
-    status = hlo.hailo_create_output_vstreams(network_group, @constCast(&output_vstream_params), output_vstream_size, output_vstreams);
+    status = hlo.hailo_create_output_vstreams(network_group, @constCast(&output_vstream_params), output_vstream_size, @constCast(&output_vstreams));
     assert(status == hlo.HAILO_SUCCESS);
 
-    status = hlo.activate_network_group(network_group, null, &activated_network_group);
-    assert(status == hlo.HAILO_SUCCESS);
-
-    defer hlo.hailo_release_output_vstreams(output_vstreams, output_vstream_size);
-    defer hlo.hailo_release_input_vstreams(input_vstreams, input_vstream_size);
-    defer hlo.hailo_release_hef(hef);
-    defer hlo.hailo_release_vdevice(vdevice);
+    defer _ = hlo.hailo_release_output_vstreams(@constCast(&output_vstreams), output_vstream_size);
+    defer _ = hlo.hailo_release_input_vstreams(@constCast(&input_vstreams), input_vstream_size);
+    defer _ = hlo.hailo_release_hef(hef);
+    defer _ = hlo.hailo_release_vdevice(vdevice);
 
     std.debug.print("output vstream size is: {any}", .{output_vstream_size});