diff --git a/nix-on-droid/nix-on-droid.sh b/nix-on-droid/nix-on-droid.sh
index 54ff4b7..51c74f9 100644
--- a/nix-on-droid/nix-on-droid.sh
+++ b/nix-on-droid/nix-on-droid.sh
@@ -1,6 +1,6 @@
 #!@bash@/bin/bash
 
-# Copyright (c) 2019-2020, see AUTHORS. Licensed under MIT License, see LICENSE.
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
 
 PATH=@coreutils@/bin:@nix@/bin:${PATH:+:}$PATH
 
@@ -73,6 +73,13 @@ function doHelp() {
     echo "                  Switch generation and activate configuration"
 }
 
+function doOnDeviceTest() {
+    # This is for maintainer convenience only, see tests/on-device/.run.sh
+    nix-channel --update nix-on-droid
+    exec "$(nix-instantiate --eval --expr \
+                            "<nix-on-droid/tests/on-device/.run.sh>")"
+}
+
 function doSwitch() {
     echo "Building activation package..."
     nix build \
@@ -114,7 +121,7 @@ while [[ $# -gt 0 ]]; do
     opt="$1"
     shift
     case $opt in
-        build|generations|help|rollback|switch|switch-generation)
+        build|generations|help|rollback|switch|switch-generation|on-device-test)
             COMMAND="$opt"
             ;;
         -f|--file)
@@ -178,6 +185,9 @@ case $COMMAND in
     help)
         doHelp
         ;;
+    on-device-test)
+        doOnDeviceTest
+        ;;
     rollback)
         if [[ $(readlink $PROFILE_DIRECTORY) =~ ^nix-on-droid-([0-9]+)-link$ ]]; then
             doSwitchGeneration $((${BASH_REMATCH[1]} - 1))
diff --git a/tests/on-device/.run.sh b/tests/on-device/.run.sh
new file mode 100755
index 0000000..246ca0c
--- /dev/null
+++ b/tests/on-device/.run.sh
@@ -0,0 +1,32 @@
+#!/usr/bin/env nix-shell
+#! nix-shell -i bash -p bats
+
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+set -ueo pipefail
+
+SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
+SELF_TEST_DIR="$HOME/.cache/nix-on-droid-self-test"
+CONFIRMATION_FILE="$SELF_TEST_DIR/confirmation-granted"
+mkdir -p "$SELF_TEST_DIR"
+
+if [[ ! -e "$CONFIRMATION_FILE" ]]; then
+    echo 'These semi-automated tests are destructive!'
+    echo 'They are meant to be executed by maintainers on a clean install.'
+    echo 'Proceeding will wreck your installation.'
+    echo 'Do you still wish to proceed?'
+    echo -n '(type "I do" to proceed, anything else to abort) > '
+    read -r CONFIRMATION
+    if [[ "$CONFIRMATION" != 'I do' ]]; then echo 'Cool, aborting.'; exit 7; fi
+    touch "$CONFIRMATION_FILE"
+fi
+
+if [[ ! -d ~/.config.bak ]]; then
+    mv ~/.config ~/.config.bak
+    cp -r ~/.config.bak ~/.config
+fi
+
+bats "${SCRIPT_DIR}" --verbose-run --timing
+
+rm -rf ~/.config
+mv ~/.config.bak ~/.config
diff --git a/tests/on-device/config-default.bats b/tests/on-device/config-default.bats
new file mode 100644
index 0000000..5565078
--- /dev/null
+++ b/tests/on-device/config-default.bats
@@ -0,0 +1,7 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+load lib
+
+@test 'default config can be switched into' {
+  switch_to_default_config
+}
diff --git a/tests/on-device/config-flake-h-m.bats b/tests/on-device/config-flake-h-m.bats
new file mode 100644
index 0000000..1085488
--- /dev/null
+++ b/tests/on-device/config-flake-h-m.bats
@@ -0,0 +1,39 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+load lib
+
+@test 'flake + h-m + #134 overlays case work' {
+  # start from a known baseline
+  switch_to_default_config
+  assert_command vi
+  assert_no_command dash zsh
+
+  # set up / build / activate the configuration
+  cat "$ON_DEVICE_TESTS_DIR/config-flake-h-m.cfg.nix" \
+    > ~/.config/nixpkgs/nix-on-droid.nix
+  nix-shell -p gnused --run \
+    "sed 's|<<FLAKE_URL>>|$FLAKE_URL|g' \
+         < '$ON_DEVICE_TESTS_DIR/config-flake-h-m.flake.nix' \
+         > ~/.config/nixpkgs/flake.nix"
+  pushd ~/.config/nixpkgs
+    nix-shell -p nixFlakes --run \
+      'nix build \
+        --extra-experimental-features nix-command \
+        --extra-experimental-features flakes \
+        --impure .#nix-on-droid'
+    result/activate
+  popd
+
+  # test presence of several crucial commands
+  assert_command nix-on-droid nix-shell bash
+
+  # test that both zsh (system) and dash (user) have appeared in $PATH
+  assert_command dash zsh
+  assert_no_command vi
+
+  # check that reverting works too
+  rm -f ~/.config/nix/nix.conf ~/.config/nixpkgs/flake.nix
+  switch_to_default_config
+  assert_command vi
+  assert_no_command dash zsh
+}
diff --git a/tests/on-device/config-flake-h-m.cfg.nix b/tests/on-device/config-flake-h-m.cfg.nix
new file mode 100644
index 0000000..2785fb0
--- /dev/null
+++ b/tests/on-device/config-flake-h-m.cfg.nix
@@ -0,0 +1,18 @@
+{ pkgs, config, ... }:
+
+{
+  system.stateVersion = "21.11";
+
+  # no nixpkgs.overlays defined
+  environment.packages = with pkgs; [ zsh ];
+
+  home-manager.config =
+    { pkgs, ... }:
+    {
+      home.stateVersion = "21.11";
+
+      nixpkgs.overlays = config.nixpkgs.overlays;
+      home.packages = with pkgs; [ dash ];
+    };
+  nixpkgs.overlays = [];
+}
diff --git a/tests/on-device/config-flake-h-m.flake.nix b/tests/on-device/config-flake-h-m.flake.nix
new file mode 100644
index 0000000..a1fc04c
--- /dev/null
+++ b/tests/on-device/config-flake-h-m.flake.nix
@@ -0,0 +1,19 @@
+{
+  description = "nix-on-droid configuration";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-21.11";
+    home-manager.url = "github:nix-community/home-manager/release-21.11";
+    nix-on-droid.url = "<<FLAKE_URL>>";
+
+    home-manager.inputs.nixpkgs.follows = "nixpkgs";
+    nix-on-droid.inputs.nixpkgs.follows = "nixpkgs";
+    nix-on-droid.inputs.home-manager.follows = "home-manager";
+  };
+
+  outputs = { nix-on-droid, ... }: {
+    nix-on-droid = (nix-on-droid.lib.aarch64-linux.nix-on-droid {
+      config = /data/data/com.termux.nix/files/home/.config/nixpkgs/nix-on-droid.nix;
+    }).activationPackage;
+  };
+}
diff --git a/tests/on-device/config-flake.bats b/tests/on-device/config-flake.bats
new file mode 100644
index 0000000..bdb6b4c
--- /dev/null
+++ b/tests/on-device/config-flake.bats
@@ -0,0 +1,43 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+load lib
+
+@test 'flake example works' {
+  # start from a known baseline
+  switch_to_default_config
+  assert_command vi
+  assert_no_command dash unzip
+
+  nix-shell -p gnused --run \
+    "sed \
+         -e s/vim/nano/ \
+         -e s/#unzip/unzip/ \
+         < '$CHANNEL_DIR/modules/environment/login/nix-on-droid.nix.default' \
+         > ~/.config/nixpkgs/nix-on-droid.nix"
+
+  nix-shell -p gnused --run \
+    "sed 's|<<FLAKE_URL>>|$FLAKE_URL|g' \
+         < '$ON_DEVICE_TESTS_DIR/config-flake.nix' \
+         > ~/.config/nixpkgs/flake.nix"
+
+  # this is more cumbersome than options,
+  # but this is what we recommend to users, so taking the hard way
+  echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf
+  pushd ~/.config/nixpkgs
+    nix-shell -p nixFlakes --run 'nix build .#nix-on-droid --impure'
+    result/activate
+  popd
+
+  # test presence of several crucial commands
+  assert_command nix-on-droid nix-shell bash
+
+  # test that nano has replaced vi and unzip has appeared in $PATH
+  assert_command nano unzip
+  assert_no_command vi
+
+  # check that reverting works too
+  rm -f ~/.config/nix/nix.conf ~/.config/nixpkgs/flake.nix
+  switch_to_default_config
+  assert_command vi
+  assert_no_command dash unzip
+}
diff --git a/tests/on-device/config-flake.nix b/tests/on-device/config-flake.nix
new file mode 100644
index 0000000..357b720
--- /dev/null
+++ b/tests/on-device/config-flake.nix
@@ -0,0 +1,15 @@
+{
+  description = "nix-on-droid configuration";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-21.11";
+    nix-on-droid.url = "<<FLAKE_URL>>";
+    nix-on-droid.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { nix-on-droid, ... }: {
+    nix-on-droid = (nix-on-droid.lib.aarch64-linux.nix-on-droid {
+      config = /data/data/com.termux.nix/files/home/.config/nixpkgs/nix-on-droid.nix;
+    }).activationPackage;
+  };
+}
diff --git a/tests/on-device/config-h-m.bats b/tests/on-device/config-h-m.bats
new file mode 100644
index 0000000..d76e393
--- /dev/null
+++ b/tests/on-device/config-h-m.bats
@@ -0,0 +1,34 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+load lib
+
+@test 'using home-manager works' {
+  # start from a known baseline
+  switch_to_default_config
+  assert_command vi
+  assert_no_command dash
+  ! [[ -e ~/.config/example ]]
+
+  nix-channel --add https://github.com/rycee/home-manager/archive/release-21.11.tar.gz home-manager
+  nix-channel --update
+  cp "$ON_DEVICE_TESTS_DIR/config-h-m.nix" ~/.config/nixpkgs/nix-on-droid.nix
+  nix-on-droid switch
+
+  # test config file
+  [[ -e ~/.config/example ]]
+  [[ "$(cat ~/.config/example)" == 'example config' ]]
+
+  # test common commands presence
+  assert_command nix-on-droid nix-shell bash
+
+  # test that vi has disappeared
+  assert_no_command vi
+
+  # test dash has appeared and works
+  assert_command dash
+  run dash -c 'echo success; exit 42'
+  [[ "$output" == success ]]
+  [[ "$status" == 42 ]]
+
+  switch_to_default_config
+}
diff --git a/tests/on-device/config-h-m.nix b/tests/on-device/config-h-m.nix
new file mode 100644
index 0000000..3da5cf1
--- /dev/null
+++ b/tests/on-device/config-h-m.nix
@@ -0,0 +1,18 @@
+{ pkgs, config, ... }:
+
+{
+  system.stateVersion = "21.11";
+
+  home-manager.config =
+    { pkgs, lib, ... }:
+    {
+      home.stateVersion = "21.11";
+      nixpkgs = { inherit (config.nixpkgs) overlays; };
+
+      # example config
+      xdg.configFile.example.text = "example config";
+
+      # example package
+      home.packages = [ pkgs.dash ];
+    };
+}
diff --git a/tests/on-device/gnumake.bats b/tests/on-device/gnumake.bats
new file mode 100644
index 0000000..97dd946
--- /dev/null
+++ b/tests/on-device/gnumake.bats
@@ -0,0 +1,14 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+@test 'GNU Make is functional' {
+  TEMPDIR=/tmp/.tmp-gnumake.$$
+  mkdir -p "$TEMPDIR"
+  echo -e 'x:\n\techo desired output > x' > "$TEMPDIR/Makefile"
+  nix-shell -p gnumake --run "make -C $TEMPDIR x"
+  [[ -e "$TEMPDIR/x" ]]
+  [[ "$(cat "$TEMPDIR/x")" == 'desired output' ]]
+}
+
+teardown() {
+  rm -r "$TEMPDIR"
+}
diff --git a/tests/on-device/hello.bats b/tests/on-device/hello.bats
new file mode 100644
index 0000000..033aefc
--- /dev/null
+++ b/tests/on-device/hello.bats
@@ -0,0 +1,7 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+@test 'GNU Hello is functional' {
+  out=$(nix-shell -p hello --run hello)
+  [[ "$out" == 'Hello, world!' ]]
+  [[ "$status" -eq 0 ]]
+}
diff --git a/tests/on-device/lib.bash b/tests/on-device/lib.bash
new file mode 100644
index 0000000..64dd54a
--- /dev/null
+++ b/tests/on-device/lib.bash
@@ -0,0 +1,47 @@
+# Copyright (c) 2019-2021, see AUTHORS. Licensed under MIT License, see LICENSE.
+
+setup() {
+  if [[ -z "$ON_DEVICE_TESTS_SETUP" ]]; then
+    CHANNEL_DIR="$(nix-instantiate --eval --expr '<nix-on-droid>')"
+    ON_DEVICE_TESTS_DIR="$CHANNEL_DIR/tests/on-device"
+
+    while read -r channel_line; do
+      if [[ "$channel_line" =~ nix-on-droid[[:space:]]+(.*) ]]; then
+        CHANNEL_URL=${BASH_REMATCH[1]}
+      fi
+    done < <(nix-channel --list)
+    echo "parsing detected channel url: $CHANNEL_URL"
+    [[ "$CHANNEL_URL" =~ https://github.com/(.+)/(.+)/archive/(.+)\.tar\.gz ]]
+    REPO_USER=${BASH_REMATCH[1]}
+    REPO_NAME=${BASH_REMATCH[2]}
+    REPO_BRANCH=${BASH_REMATCH[3]}
+    FLAKE_URL=github:$REPO_USER/$REPO_NAME/$REPO_BRANCH
+    echo "autodetected flake url: $FLAKE_URL"
+
+    ON_DEVICE_TESTS_SETUP=1
+  fi
+}
+
+assert_command() {
+  for cmd_name; do
+    command -v "$cmd_name"
+  done
+}
+
+assert_no_command() {
+  for cmd_name; do
+    run command -v "$cmd_name"
+    [[ "$status" == 1 ]]
+  done
+}
+
+switch_to_default_config() {
+  rm -rf ~/.config/nix ~/.config/nixpkgs
+  mkdir -p ~/.config/nix ~/.config/nixpkgs
+  cat "$CHANNEL_DIR/modules/environment/login/nix-on-droid.nix.default" \
+    > ~/.config/nixpkgs/nix-on-droid.nix
+  nix-on-droid switch
+
+  assert_command nix-on-droid nix-shell bash vi find
+  assert_no_command dash xonsh zsh
+}