diff --git a/08-interop/compile_contiki.sh b/08-interop/compile_contiki.sh
new file mode 100755
index 0000000..b4454c1
--- /dev/null
+++ b/08-interop/compile_contiki.sh
@@ -0,0 +1,29 @@
+#!/bin/bash
+
+cd /tmp
+
+# Clone Contiki-NG
+git clone https://github.com/contiki-ng/contiki-ng.git; cd contiki-ng || \
+cd contiki-ng; git pull
+git submodule update --init --recursive
+
+# Pull the Contiki-NG Docker image
+docker pull contiker/contiki-ng
+
+# Add the `shell` service to the `examples/hello-world` application.
+if ! grep -q "MODULES += os/services/shell" examples/hello-world/Makefile; then
+    sed -i '/all: $(CONTIKI_PROJECT)/a\\nMODULES += os/services/shell\n' examples/hello-world/Makefile
+fi
+
+
+# Compile the `examples/hello-world` application for the nRF52840 platform.
+export CNG_PATH=/tmp/contiki-ng
+docker run \
+    --privileged \
+    --sysctl net.ipv6.conf.all.disable_ipv6=0 \
+    --mount type=bind,source=$CNG_PATH,destination=/home/user/contiki-ng \
+    -e DISPLAY=$DISPLAY \
+    -v /tmp/.X11-unix:/tmp/.X11-unix \
+    -v /dev/bus/usb:/dev/bus/usb \
+    contiker/contiki-ng \
+    make -C examples/hello-world TARGET=nrf52840 hello-world
diff --git a/08-interop/test_spec08.py b/08-interop/test_spec08.py
old mode 100644
new mode 100755
index dae060e..b69826e
--- a/08-interop/test_spec08.py
+++ b/08-interop/test_spec08.py
@@ -1,5 +1,6 @@
 import re
 import sys
+import subprocess
 
 import pexpect.replwrap
 import pytest
@@ -49,6 +50,36 @@ def test_task01(riot_ctrl, log_nodes):
     assert res["stats"]["packet_loss"] < 1
 
 
+@pytest.mark.flaky(reruns=1, reruns_delay=30)
+@pytest.mark.iotlab_creds
+# nodes passed to riot_ctrl fixture
+@pytest.mark.parametrize(
+    'nodes', [pytest.param(['nrf52840dk', 'nrf52840dk'])], indirect=['nodes']
+)
+def test_task03(riot_ctrl):
+    # run `./compile_contiki.sh` relative to this file
+    subprocess.check_call(["./compile_contiki.sh"], cwd=__file__[:__file__.rfind("/")])
+
+    gnrc_node, contiki_node = (
+        riot_ctrl(0, GNRC_APP, Shell),
+        riot_ctrl(1, 'examples/hello-world', riotctrl.shell.ShellInteraction, extras={"BINFILE": "/tmp/contiki-ng/examples/hello-world/build/nrf52840/dk/hello-world.nrf52840"}),
+    )
+
+    gnrc_netif, gnrc_addr = lladdr(gnrc_node.ifconfig_list())
+
+    # get the address of the contiki node, ie a substring after "-- "
+    res = contiki_node.cmd("ip-addr")
+    contiki_addr = res[res.find("-- ") + 3:]
+
+    gnrc_node.ifconfig_set(gnrc_netif, "pan_id", "abcd")
+
+    res = contiki_node.cmd(f"ping {gnrc_addr}")
+    assert f"Received ping reply from {gnrc_addr}" in res
+
+    res = ping6(gnrc_node, contiki_addr, 3, 12, 1)
+    assert res['stats']['packet_loss'] < 10
+
+
 @pytest.mark.flaky(reruns=3, reruns_delay=30)
 @pytest.mark.iotlab_creds
 # nodes passed to riot_ctrl fixture
diff --git a/conftest.py b/conftest.py
index a3bc5e8..e6b1861 100644
--- a/conftest.py
+++ b/conftest.py
@@ -303,7 +303,7 @@ def nodes(local, request, boards, iotlab_site):
         RUNNING_EXPERIMENTS.remove(exp)
 
 
-def update_env(node, modules=None, cflags=None, port=None, termflags=None):
+def update_env(node, modules=None, cflags=None, port=None, termflags=None, extras=None):
     node.env['QUIETER'] = '1'
     if not isinstance(modules, str) and isinstance(modules, Iterable):
         node.env['USEMODULE'] = ' '.join(str(m) for m in modules)
@@ -322,6 +322,8 @@ def update_env(node, modules=None, cflags=None, port=None, termflags=None):
         node.env['PORT'] = port
     if termflags is not None:
         node.env['TERMFLAGS'] = termflags
+    if extras is not None:
+        node.env.update(extras)
 
 
 @pytest.fixture
@@ -342,12 +344,13 @@ def ctrl(
         cflags=None,
         port=None,
         termflags=None,
+        extras=None,
     ):
         if board_type is not None:
             node = next(n for n in nodes if n.board() == board_type)
         else:
             node = nodes[nodes_idx]
-        update_env(node, modules, cflags, port, termflags)
+        update_env(node, modules, cflags, port, termflags, extras)
         # if the nodes are not logged, there is no sense in logging to a file
         # so check if nodes are logged as well as if they should be logged to a
         # file
@@ -366,8 +369,11 @@ def ctrl(
         # need to access private member here isn't possible otherwise sadly :(
         # pylint: disable=W0212
         node._application_directory = os.path.join(riotbase, application_dir)
+        flash_cmd = "flash"
+        if "BINFILE" in node.env:
+            flash_cmd = "flash-only"
         node.make_run(
-            ['flash'],
+            [flash_cmd],
             check=True,
             stdout=None if log_nodes else subprocess.DEVNULL,
             stderr=None if log_nodes else subprocess.DEVNULL,