diff --git a/aruco_pose/test/largemap.py b/aruco_pose/test/largemap.py
index 56e06837..e27fe570 100755
--- a/aruco_pose/test/largemap.py
+++ b/aruco_pose/test/largemap.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import sys
 import unittest
 import json
diff --git a/builder/assets/butterfly.service b/builder/assets/butterfly.service
index a822c816..7b7c890d 100644
--- a/builder/assets/butterfly.service
+++ b/builder/assets/butterfly.service
@@ -2,5 +2,5 @@
 Description=Butterfly Terminal Server
 
 [Service]
-ExecStart=/usr/local/bin/butterfly.server.py --host="0.0.0.0" --unsecure
+ExecStart=/bin/bash -c ". /root/butterfly_env/bin/activate; butterfly.server.py --host="0.0.0.0" --unsecure"
 User=pi
diff --git a/builder/assets/python3.yaml b/builder/assets/python3.yaml
new file mode 100644
index 00000000..fc5f4879
--- /dev/null
+++ b/builder/assets/python3.yaml
@@ -0,0 +1,22 @@
+python3-crypto:
+  debian:
+    buster: [python3-crypto]
+python3-imaging:
+  debian:
+    buster: [python3-pil]
+python3-wxtools:
+  debian:
+    pip:
+      packages: [wxPython]
+python3-future:
+  debian:
+    buster: [python3-future]
+python3-twisted:
+  debian:
+    buster: [python3-twisted]
+python3-serial:
+  debian:
+    buster: [python3-serial]
+python3-requests:
+  debian:
+    buster: [python3-requests]
diff --git a/builder/image-build.sh b/builder/image-build.sh
index 957f1d01..acb62484 100755
--- a/builder/image-build.sh
+++ b/builder/image-build.sh
@@ -111,6 +111,7 @@ ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} exec ${SCRIPTS_DIR}'/image-network.
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/clever.service' '/lib/systemd/system/'
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/roscore.service' '/lib/systemd/system/'
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/melodic-rosdep-clever.yaml' '/etc/ros/rosdep/'
+${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/python3.yaml' '/etc/ros/rosdep/'
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/ros_python_paths' '/etc/sudoers.d/'
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/pigpiod.service' '/lib/systemd/system/'
 ${BUILDER_DIR}/image-chroot.sh ${IMAGE_PATH} copy ${SCRIPTS_DIR}'/assets/launch.nanorc' '/usr/share/nano/'
diff --git a/builder/image-ros.sh b/builder/image-ros.sh
index 26e7ca37..2b1fc6a8 100755
--- a/builder/image-ros.sh
+++ b/builder/image-ros.sh
@@ -68,7 +68,8 @@ my_travis_retry() {
 # TODO: 'kinetic-rosdep-clever.yaml' should add only if we use our repo?
 echo_stamp "Init rosdep"
 my_travis_retry rosdep init
-echo "yaml file:///etc/ros/rosdep/melodic-rosdep-clever.yaml" >> /etc/ros/rosdep/sources.list.d/20-default.list
+echo "yaml file:///etc/ros/rosdep/melodic-rosdep-clever.yaml" > /etc/ros/rosdep/sources.list.d/30-clever.list
+echo "yaml file:///etc/ros/rosdep/python3.yaml" > /etc/ros/rosdep/sources.list.d/40-python3.list
 my_travis_retry rosdep update
 
 echo_stamp "Populate rosdep for ROS user"
@@ -97,8 +98,9 @@ echo_stamp "Installing CLEVER" \
 && git status \
 && cd /home/pi/catkin_ws \
 && resolve_rosdep $(pwd) \
-&& my_travis_retry pip install wheel \
-&& my_travis_retry pip install -r /home/pi/catkin_ws/src/clever/clever/requirements.txt \
+&& my_travis_retry pip3 install wheel \
+&& my_travis_retry pip3 install -r /home/pi/catkin_ws/src/clever/clever/requirements.txt \
+&& export ROS_PYTHON_VERSION=3 \
 && source /opt/ros/melodic/setup.bash \
 && catkin_make -j2 -DCMAKE_BUILD_TYPE=Release \
 && systemctl enable roscore \
@@ -128,8 +130,7 @@ echo_stamp "Install GeographicLib datasets (needed for mavros)" \
 && wget -qO- https://raw.githubusercontent.com/mavlink/mavros/master/mavros/scripts/install_geographiclib_datasets.sh | bash
 
 # FIXME: Buster comes with tornado==5.1.1 but we need tornado==4.2.1 for rosbridge_suite
-# (note that Python 3 will still have a more recent version)
-pip install tornado==4.2.1
+pip3 install tornado==4.2.1
 
 echo_stamp "Running tests"
 cd /home/pi/catkin_ws
diff --git a/builder/image-software.sh b/builder/image-software.sh
index cb4e5746..e70877c6 100755
--- a/builder/image-software.sh
+++ b/builder/image-software.sh
@@ -66,7 +66,8 @@ apt-get update \
 && apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654
 
 echo "deb http://packages.ros.org/ros/ubuntu buster main" > /etc/apt/sources.list.d/ros-latest.list
-echo "deb http://deb.coex.tech/rpi-ros-melodic buster main" > /etc/apt/sources.list.d/rpi-ros-melodic.list
+echo "deb http://deb.coex.tech/opencv3 buster main" > /etc/apt/sources.list.d/opencv3.list
+echo "deb http://deb.coex.tech/melodic-py3 buster main" > /etc/apt/sources.list.d/rpi-ros-melodic.list
 # FIXME: We still don't have these packages built for Buster
 # FIXME: Check these packages after their installation
 echo "deb http://deb.coex.tech/clever stretch main" > /etc/apt/sources.list.d/clever.list
@@ -109,6 +110,7 @@ espeak espeak-data python-espeak \
 ntpdate \
 python-dev \
 python3-dev \
+python3-venv \
 python-systemd \
 mjpg-streamer \
 && echo_stamp "Everything was installed!" "SUCCESS" \
@@ -132,10 +134,14 @@ pip3 --version
 
 echo_stamp "Install and enable Butterfly (web terminal)"
 echo_stamp "Workaround for tornado >= 6.0 breaking butterfly"
-my_travis_retry pip3 install tornado==5.1.1
-my_travis_retry pip3 install butterfly
-my_travis_retry pip3 install butterfly[systemd]
+cd /root
+python3 -m venv butterfly_env
+source butterfly_env/bin/activate
+my_travis_retry pip install tornado==5.1.1
+my_travis_retry pip install butterfly
+my_travis_retry pip install butterfly[systemd]
 systemctl enable butterfly.socket
+deactivate
 
 echo_stamp "Install ws281x library"
 my_travis_retry pip install --prefer-binary rpi_ws281x
diff --git a/builder/image-validate.sh b/builder/image-validate.sh
index ce30379e..0391dd51 100755
--- a/builder/image-validate.sh
+++ b/builder/image-validate.sh
@@ -18,6 +18,7 @@ echo "Run image tests"
 
 export ROS_DISTRO='melodic'
 export ROS_IP='127.0.0.1'
+export ROS_PYTHON_VERSION=3
 source /opt/ros/melodic/setup.bash
 source /home/pi/catkin_ws/devel/setup.bash
 
diff --git a/builder/test/tests.py b/builder/test/tests.py
index 6d7f6e60..380ff29b 100755
--- a/builder/test/tests.py
+++ b/builder/test/tests.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # validate all required modules installed
 
@@ -27,4 +27,4 @@ import rpi_ws281x
 import pigpio
 from espeak import espeak
 
-print cv2.getBuildInformation()
+print(cv2.getBuildInformation())
diff --git a/clever/test/basic.py b/clever/test/basic.py
index 67de1fbe..3816562a 100755
--- a/clever/test/basic.py
+++ b/clever/test/basic.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 import rospy
 import pytest
 from mavros_msgs.msg import State