fix(security): re-harden root sudo helpers; installer fixes; ARCHITECTURE and PERMISSIONS docs (#640)

* docs: add ARCHITECTURE and PERMISSIONS guides

ARCHITECTURE.md maps the processes, the state the display and web
services share through the cache, the display loop, the plugin system,
the web UI and the update path, with links into the code and a
where-to-start table.

PERMISSIONS.md lists who owns what after install, both sudoers files
(and why iptables is not granted), the polkit rule, and which
scripts/fix_perms script to run as which user.

Both are linked from the docs index, along with the MQTT bridge README
and src/common/README.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: correct stale setup, service and troubleshooting claims

- README: quick actions run systemctl on ledmatrix.service (run.py), not
  display_controller.py; use_short_date_format has no effect; the
  installer uses system pip with --break-system-packages, not a venv.
- CONFIG_DEBUGGING: LEDMATRIX_DEBUG must be "true"; logs are in journald.
- GETTING_STARTED, WEB_INTERFACE_GUIDE, TROUBLESHOOTING: enabling a
  plugin, plugin settings, brightness and Vegas settings apply without a
  restart; matrix hardware settings still need one.
- TROUBLESHOOTING: install dependencies with sudo so the root service
  sees them; point permission problems at PERMISSIONS.md instead of a
  project-wide chown.
- ADVANCED_FEATURES: real BackgroundDataService stats keys; Vegas hooks
  return VegasDisplayMode and None falls back to capture; cache files
  are 0660; fix_web_permissions.sh runs as the web user and does not
  touch sudoers.
- STARLARK_APPS_GUIDE: only the linux-arm64 pixlet binary is downloaded.
- HOW_TO_RUN_TESTS: test class examples that exist.
- CLAUDE.md: PluginStoreManager, plugin_dirs.py, monorepo installs via
  the Trees API with ZIP fallback, requirements.txt is optional.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: mark deprecated plugin APIs and state manifest fields once

Methods @deprecated("3.7.0") (the set pinned in test_deprecation.py)
were shown as current API in the quick reference, API reference,
advanced guide, development guide and FONT_MANAGER. Each is now marked
deprecated with its replacement. FONT_MANAGER is rewritten around the
current API; the override editor is gone and override methods are
deprecated.

Required manifest fields were stated three different ways. The API
reference now has one section: the 7 schema-required fields, the 4 the
store refuses without, class_name for the loader, and the 8 to set.
The other guides link to it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: document every src/common module and every widget

- src/common/README.md covered 7 of 17 modules. It now has a table of
  all of them (purpose, whether plugins import it, release to floor
  on), a short entry each, and logging advice that matches the code.
- SPORTS_UNIFICATION listed two shared modules and called
  sports_helpers the first; it now lists all six.
- The widgets README lists all 28 registered widgets plus the support
  files, and absorbs the parts that only docs/widget-guide.md had
  (x-options.labels, x-advanced, x-display hidden, plugin-file-manager).
  docs/widget-guide.md is now a pointer to it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(security): fix_web_permissions.sh re-hardens the root sudo helpers

The script chowns the whole project to the web user. That included
scripts/fix_perms/safe_plugin_rm.sh and safe_pip_install.sh -- the two
helpers /etc/sudoers.d/ledmatrix_web lets the web user run as root -- so
running it turned both into a root shell for whoever can edit them. It
also re-grouped config_secrets.json away from ledmatrix.

After the chown it now does what first_time_install.sh's Steps 11 and
11.1 do: helpers back to root:root 755, and config_secrets.json back to
the web unit's User=:ledmatrix 640. Each step is non-fatal and prints the
manual command if it fails.

Also fixes what the script and its docs claimed: it never configured
sudoers, its closing hint pointed at ./configure_web_sudo.sh (wrong
path), and the README and ADVANCED_FEATURES.md said to run it with sudo,
which it refuses.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(security): validate and harden every sudoers drop-in the scripts write

configure_wifi_permissions.sh copied its rules into
/etc/sudoers.d/ledmatrix_wifi without `visudo -c`. A malformed drop-in
makes sudo refuse every command for every user, which on a headless Pi
leaves no way back in. It now checks first and leaves the installed file
alone when the rules do not parse, as the other two writers do. (It
already used mktemp, so that part of the review did not apply.)

It also grants the two literal commands wifi_manager.py runs for
NetworkManager's shared-mode dnsmasq drop-in -- `cp
/tmp/ledmatrix-nm-dnsmasq.conf .../dnsmasq-shared.d/ledmatrix-captive.conf`
and `rm -f` of that file. The directory's mkdir was granted, the file was
not. Both are pinned in test_sudo_allowlist_covers_calls.py.

configure_web_sudo.sh wrote its rules to /tmp/ledmatrix_web_sudoers_$$,
a predictable name in a world-writable directory; it now uses mktemp with
an EXIT trap, as first_time_install.sh does. It sets mode 440 on the
installed file instead of leaving the temp file's mode, and finds visudo
in /usr/sbin when that is not on the user's PATH, which skipped the
check silently.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): escape the project path in the DNS-fix and MQTT unit renderers

install_dns_fix.sh and install_mqtt_bridge.sh substituted
__PROJECT_ROOT_DIR__ with the raw path, while the other three renderers
go through sed_escape_replacement from lib_systemd_render.sh. A checkout
under a path containing `&`, `\` or `|` rendered a corrupted unit from
these two only. Both now source the helper and use it, and a test checks
that every placeholder substitution in scripts/install uses an escaped
value.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): stop the installer scripts reporting things that are not true

- first_time_install.sh printed "Password: ledmatrix123" for the setup
  access point. wifi_manager creates it as an open network ("No
  password" on the panel), so it now says so.
- Step 10.1 printed "✓ WiFi management permissions configured" straight
  after its own failure message; install_wifi_monitor.sh printed
  "✓ Package installation completed" after a failed apt install. The
  tick now only follows success.
- Step 7 printed "Web dependencies already installed ... in Step 5" in
  the one branch that runs because Step 5 did not install them, then
  created .web_deps_installed on that basis. It now warns and leaves the
  marker off so the next run retries, as the comment below it intends.
- check_system_compatibility.sh called Debian 12 Bookworm "full
  compatibility confirmed" while first_time_install.sh refuses anything
  but Debian 13. Bookworm, older Debian and non-Debian systems are now
  errors. Its counters used ((X++)), which under `set -e` exits the
  script at the first warning or error (the expression is 0), so the
  check never reached its summary on any system with one.
- configure_web_sudo.sh and configure_wifi_permissions.sh finished by
  testing `sudo -n test -f ...` and `sudo -n nmcli device status`,
  neither of which is granted, so they always reported a failure. They
  now ask `sudo -n -l` about commands the new rules do grant, which
  checks the rule without running anything.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): print the completion summary before rebooting

With -y -- and so for every one-shot `curl | bash` install, which always
passes -y -- first_time_install.sh ran `reboot` about 180 lines before
its "Installation Complete / Web UI Access" summary. reboot returns at
once, so the summary printed while the Pi was going down and the SSH
session usually dropped before the web UI address could be read.

The reboot block moves, unchanged, to the very end of the script. The
interactive prompt now also follows the summary. Because the summary now
runs before the -y reboot, its one command that could fail under
`set -Eeuo pipefail` (the SSID lookup, when nmcli reports a connected
device but no active network line) gets `|| true`; a missing SSID was
already handled as "SSID unknown".

one-shot-install.sh prints its "Next steps" after the installer returns,
by which time the reboot is under way, so it now says so, and README's
Quick Install mentions the automatic reboot.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* chore(scripts): correct wrong comments and messages, drop dead code

No behaviour change except the output text noted below.

- 2775 is setgid, not the sticky bit (first_time_install.sh Step 3.1,
  fix_plugin_permissions.sh), and root needs no "PWM hardware access"
  to plugin files.
- The 777 comments in first_time_install.sh Step 3's fallback and
  fix_assets_permissions.sh said root needs it to write. Root ignores
  mode bits; the comments now say what 777 actually opens. The 777
  itself is unchanged.
- apt_remove ends in `|| true`, so Step 12's "Some packages could not be
  removed" branch could never run; it is gone and the helper stays
  non-fatal.
- detect_web_service_user's comment named Step 8 for the web unit
  (install_service.sh installs it in Step 7.5) and now says which
  branch actually runs.
- Step 5 described an "already installed" check that does not exist;
  the ACTUAL_USER comment described the re-exec backwards.
- on_error printed a literal "\n" before "Common fixes:".
- Dead code: one-shot-install.sh's uncalled fix_tmp_permissions,
  LEDMATRIX_ELEVATED=1 (never read) on the sudo re-exec, and
  configure_web_sudo.sh's unused PYTHON_PATH, which also made a missing
  python3 fatal for rules that never mention it.
- start_display.sh / stop_display.sh said "for user: <you>"; the
  service runs as root.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* refactor(fix_perms): fix_cache_permissions.sh uses setup_cache.sh's model

There were two models for /var/cache/ledmatrix. setup_cache.sh (the
installer's Step 2) and install_web_service.sh share it through the
ledmatrix group: root:ledmatrix, 2775, files 660, which is also what
DiskCache relies on to give files the directory's group.
fix_cache_permissions.sh instead made it 777 and re-grouped it to the
invoking user's group, undoing that.

It now runs setup_cache.sh for /var/cache/ledmatrix and keeps its own
handling of ~/.ledmatrix_cache. Dropped: /var/cache/ledmatrix/
placeholder_logos (nothing reads it) and the checks against the
`daemon` user (no service runs as daemon).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* ci: pin actions/checkout in the Claude workflows, drop template comments

claude.yml and claude-code-review.yml used actions/checkout@v4 while
test.yml and release-version-check.yml pin the v4.2.2 commit SHA; they
now pin the same SHA. The commented-out starter-template settings
(prompt, claude_args, paths, author filter) are removed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(scripts): index every script and list removal candidates

New scripts/README.md gives one line per top-level script and scripts
directory, marked keep, dev-only or diagnostic, and lists the eight
scripts nothing in the repo refers to as candidates for removal (kept
for now). The install, utils and dev READMEs now list the files they
were missing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* test: tighten two checks that mutation testing showed were too loose

- The wifi sudoers check matched `visudo -c -f "$TEMP_SUDOERS"` in the
  error report too, so replacing the check with `if false` still passed.
  It now requires the command as the condition.
- The summary test never had the setup access point up, so reinstating
  the bogus "Password: ledmatrix123" line went unnoticed. A case with
  hostapd active now checks the AP is described as open.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(permissions): describe the repaired fix_perms scripts and new WiFi grants

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(changelog): docs-scripts

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

scripts/install/README.md

@@ -19,6 +19,21 @@ This directory contains scripts for installing and configuring the LEDMatrix sys
   (the user who runs the script, i.e. the one you installed LEDMatrix as;
   there is no `ledmatrix` system user) the passwordless `nmcli` and related
   WiFi permissions the web interface needs
+- **`install_dns_fix.sh`** - Optional. Installs `ledmatrix-dns-fix.service`,
+  which adds `options single-request` to the resolver when API calls time
+  out (see `systemd/README.md`)
+- **`install_mqtt_bridge.sh`** - Optional. Installs the Home Assistant MQTT
+  bridge service (see `integrations/mqtt_bridge/README.md`)
+
+Libraries (sourced, not run):
+
+- **`lib_sudoers.sh`** - The web interface's sudo allow-list
+  (`/etc/sudoers.d/ledmatrix_web`), shared by `first_time_install.sh` and
+  `configure_web_sudo.sh`
+- **`lib_systemd_render.sh`** - `sed_escape_replacement`, used by every
+  script that renders a unit from `systemd/*.service`
+- **`lib_lowmem.sh`** - Build-job sizing and temporary swap for the C++
+  build on low-memory Pis (`first_time_install.sh` Step 6)
 
 ## Usage
 

scripts/install/configure_web_sudo.sh

@@ -26,7 +26,6 @@ fi
 # Get the full paths to commands and validate each one
 MISSING_CMDS=()
 
-PYTHON_PATH=$(command -v python3)   || true
 SYSTEMCTL_PATH=$(command -v systemctl) || true
 REBOOT_PATH=$(command -v reboot)    || true
 POWEROFF_PATH=$(command -v poweroff)  || true
@@ -35,8 +34,8 @@ JOURNALCTL_PATH=$(command -v journalctl) || true
 SAFE_RM_PATH="$PROJECT_ROOT/scripts/fix_perms/safe_plugin_rm.sh"
 SAFE_PIP_INSTALL_PATH="$PROJECT_ROOT/scripts/fix_perms/safe_pip_install.sh"
 
-# Validate required commands (systemctl, bash, python3 are essential)
-for CMD_NAME in SYSTEMCTL_PATH BASH_PATH PYTHON_PATH; do
+# Validate required commands (systemctl and bash are essential)
+for CMD_NAME in SYSTEMCTL_PATH BASH_PATH; do
     CMD_VAL="${!CMD_NAME}"
     if [ -z "$CMD_VAL" ]; then
         MISSING_CMDS+=("$CMD_NAME")
@@ -70,7 +69,6 @@ fi
 . "$SUDOERS_LIB"
 
 echo "Command paths:"
-echo "  Python: $PYTHON_PATH"
 echo "  Systemctl: $SYSTEMCTL_PATH"
 echo "  Reboot: ${REBOOT_PATH:-(not found, skipping)}"
 echo "  Poweroff: ${POWEROFF_PATH:-(not found, skipping)}"
@@ -79,14 +77,24 @@ echo "  Journalctl: ${JOURNALCTL_PATH:-(not found, skipping)}"
 echo "  Safe plugin rm: $SAFE_RM_PATH"
 echo "  Safe pip install: $SAFE_PIP_INSTALL_PATH"
 
-# Create a temporary sudoers file
-TEMP_SUDOERS="/tmp/ledmatrix_web_sudoers_$$"
+# Create a temporary sudoers file. A predictable name in a world-writable
+# directory is a symlink target, and these rules end up in /etc/sudoers.d, so
+# let mktemp pick the name; the trap removes it however the script ends.
+TEMP_SUDOERS=$(mktemp "${TMPDIR:-/tmp}/ledmatrix_web_sudoers.XXXXXX") || {
+    echo "Error: could not create a temporary file" >&2
+    exit 1
+}
+trap 'rm -f "$TEMP_SUDOERS"' EXIT
 
 web_sudoers_rules "$WEB_USER" "$PROJECT_ROOT" "$SYSTEMCTL_PATH" "$BASH_PATH" \
     "$REBOOT_PATH" "$POWEROFF_PATH" "$JOURNALCTL_PATH" > "$TEMP_SUDOERS"
 
 # Never offer to install rules we have not parsed. A malformed drop-in in
 # /etc/sudoers.d makes sudo refuse every command for every user.
+# visudo lives in /usr/sbin, which is not on every user's PATH.
+if ! command -v visudo >/dev/null 2>&1 && [ -x /usr/sbin/visudo ]; then
+    PATH="$PATH:/usr/sbin"
+fi
 if command -v visudo >/dev/null 2>&1; then
     if ! visudo -c -f "$TEMP_SUDOERS" >/dev/null 2>&1; then
         echo ""
@@ -96,6 +104,8 @@ if command -v visudo >/dev/null 2>&1; then
         rm -f "$TEMP_SUDOERS"
         exit 1
     fi
+else
+    echo "⚠ visudo not found; the rules below have not been validated"
 fi
 
 echo ""
@@ -124,7 +134,7 @@ if [[ ! $REPLY =~ ^[Yy]$ ]]; then
     exit 0
 fi
 
-# Apply the configuration using visudo
+# Apply the configuration
 echo "Applying sudoers configuration..."
 # Harden the helper script: root-owned, not writable by web user
 echo "Hardening safe_plugin_rm.sh ownership..."
@@ -143,21 +153,29 @@ if ! sudo chmod 755 "$SAFE_PIP_INSTALL_PATH"; then
 fi
 
 if sudo cp "$TEMP_SUDOERS" /etc/sudoers.d/ledmatrix_web; then
+    # sudo reads /etc/sudoers.d files that are root-owned and not writable by
+    # group or other; 440 is the mode visudo and first_time_install.sh use.
+    if ! sudo chmod 440 /etc/sudoers.d/ledmatrix_web; then
+        echo "Warning: could not set mode 440 on /etc/sudoers.d/ledmatrix_web"
+    fi
     echo "Configuration applied successfully!"
     echo ""
     echo "Testing sudo access..."
     
-    # Test a few commands
-    if sudo -n systemctl status ledmatrix.service > /dev/null 2>&1; then
+    # Ask sudo whether two of the new rules let this user in without a
+    # password. `sudo -l CMD` answers from the rules without running CMD, so
+    # this does not depend on whether ledmatrix.service is running, and it
+    # tests commands the rules actually grant.
+    if sudo -n -l "$SYSTEMCTL_PATH" status ledmatrix.service > /dev/null 2>&1; then
         echo "✓ systemctl status ledmatrix.service - OK"
     else
-        echo "✗ systemctl status ledmatrix.service - Failed"
+        echo "✗ systemctl status ledmatrix.service - not allowed without a password"
     fi
-    
-    if sudo -n test -f "$PROJECT_ROOT/start_display.sh"; then
-        echo "✓ File access test - OK"
+
+    if sudo -n -l "$BASH_PATH" "$SAFE_RM_PATH" "$PROJECT_ROOT/plugin-repos/example" > /dev/null 2>&1; then
+        echo "✓ safe_plugin_rm.sh helper - OK"
     else
-        echo "✗ File access test - Failed"
+        echo "✗ safe_plugin_rm.sh helper - not allowed without a password"
     fi
     
     echo ""

scripts/install/configure_wifi_permissions.sh

@@ -144,6 +144,11 @@ $WEB_USER ALL=(ALL) NOPASSWD: $MKDIR_PATH -p /etc/NetworkManager/dnsmasq-shared.
 $WEB_USER ALL=(ALL) NOPASSWD: /usr/bin/cp /tmp/hostapd.conf /etc/hostapd/hostapd.conf
 $WEB_USER ALL=(ALL) NOPASSWD: /usr/bin/cp /tmp/dnsmasq.conf /etc/dnsmasq.d/ledmatrix-captive.conf
 $WEB_USER ALL=(ALL) NOPASSWD: /usr/bin/rm -f /etc/dnsmasq.d/ledmatrix-captive.conf
+# The same captive-portal DNS drop-in for NetworkManager's shared-mode dnsmasq
+# (wifi_manager._write_nm_dnsmasq_captive_conf / _remove_nm_dnsmasq_captive_conf),
+# exact paths.
+$WEB_USER ALL=(ALL) NOPASSWD: /usr/bin/cp /tmp/ledmatrix-nm-dnsmasq.conf /etc/NetworkManager/dnsmasq-shared.d/ledmatrix-captive.conf
+$WEB_USER ALL=(ALL) NOPASSWD: /usr/bin/rm -f /etc/NetworkManager/dnsmasq-shared.d/ledmatrix-captive.conf
 EOF
 
 echo "Generated sudoers configuration:"
@@ -151,6 +156,21 @@ echo "--------------------------------"
 cat "$TEMP_SUDOERS"
 echo "--------------------------------"
 
+# Never install rules we have not parsed. A malformed drop-in in
+# /etc/sudoers.d makes sudo refuse every command for every user, which on a
+# headless Pi leaves no way in at all. first_time_install.sh and
+# configure_web_sudo.sh check their rules the same way.
+if command -v visudo >/dev/null 2>&1; then
+    if ! visudo -c -f "$TEMP_SUDOERS" >/dev/null 2>&1; then
+        echo "✗ The generated sudoers rules did not parse:" >&2
+        visudo -c -f "$TEMP_SUDOERS" >&2 || true
+        echo "  Leaving $SUDOERS_FILE unchanged." >&2
+        exit 1
+    fi
+else
+    echo "⚠ visudo not found; installing the sudoers rules unvalidated"
+fi
+
 # Apply the sudoers configuration
 echo ""
 echo "Applying sudoers configuration..."
@@ -213,11 +233,14 @@ rm -f "$TEMP_POLKIT"
 echo ""
 echo "Step 3: Testing permissions..."
 
-# Test sudo access
-if sudo -n "$NMCLI_PATH" device status > /dev/null 2>&1; then
-    echo "✓ nmcli device status - OK"
+# Ask sudo whether one of the new rules lets this user in without a password.
+# `sudo -l CMD` answers from the rules without running CMD, so the radio is
+# left alone. (This used to run `nmcli device status`, which is not granted,
+# so it could only ever report a failure.)
+if sudo -n -l "$NMCLI_PATH" radio wifi on > /dev/null 2>&1; then
+    echo "✓ nmcli radio wifi on - OK"
 else
-    echo "✗ nmcli device status - Failed (this is expected if not connected)"
+    echo "✗ nmcli radio wifi on - not allowed without a password"
 fi
 
 echo ""

scripts/install/install_dns_fix.sh

@@ -10,6 +10,10 @@
 set -e
 
 PROJECT_ROOT_DIR=$(cd "$(dirname "$0")/../.." && pwd)
+
+# shellcheck source=scripts/install/lib_systemd_render.sh
+source "$PROJECT_ROOT_DIR/scripts/install/lib_systemd_render.sh"
+
 SERVICE_NAME="ledmatrix-dns-fix"
 UNIT_SRC="$PROJECT_ROOT_DIR/systemd/$SERVICE_NAME.service"
 UNIT_DEST="/etc/systemd/system/$SERVICE_NAME.service"
@@ -34,7 +38,8 @@ fi
 chmod +x "$PROJECT_ROOT_DIR/scripts/utils/apply_dns_single_request.sh"
 
 echo "Installing $UNIT_DEST..."
-sed "s|__PROJECT_ROOT_DIR__|$PROJECT_ROOT_DIR|g" "$UNIT_SRC" \
+ESCAPED_PROJECT_ROOT_DIR=$(sed_escape_replacement "$PROJECT_ROOT_DIR")
+sed "s|__PROJECT_ROOT_DIR__|$ESCAPED_PROJECT_ROOT_DIR|g" "$UNIT_SRC" \
     | $SUDO tee "$UNIT_DEST" > /dev/null
 
 # Order ledmatrix.service after the fix. `Before=` in the unit itself only

scripts/install/install_mqtt_bridge.sh

@@ -9,6 +9,10 @@
 set -e
 
 PROJECT_ROOT_DIR=$(cd "$(dirname "$0")/../.." && pwd)
+
+# shellcheck source=scripts/install/lib_systemd_render.sh
+source "$PROJECT_ROOT_DIR/scripts/install/lib_systemd_render.sh"
+
 BRIDGE_DIR="$PROJECT_ROOT_DIR/integrations/mqtt_bridge"
 SERVICE_NAME="ledmatrix-mqtt-bridge"
 UNIT_SRC="$PROJECT_ROOT_DIR/systemd/$SERVICE_NAME.service"
@@ -40,7 +44,8 @@ python3 -m pip install -r "$BRIDGE_DIR/requirements.txt" 2>/dev/null \
     || python3 -m pip install --break-system-packages -r "$BRIDGE_DIR/requirements.txt"
 
 echo "Installing $UNIT_DEST..."
-sed "s|__PROJECT_ROOT_DIR__|$PROJECT_ROOT_DIR|g" "$UNIT_SRC" \
+ESCAPED_PROJECT_ROOT_DIR=$(sed_escape_replacement "$PROJECT_ROOT_DIR")
+sed "s|__PROJECT_ROOT_DIR__|$ESCAPED_PROJECT_ROOT_DIR|g" "$UNIT_SRC" \
     | $SUDO tee "$UNIT_DEST" > /dev/null
 
 $SYSTEMCTL_CMD daemon-reload

scripts/install/install_wifi_monitor.sh

@@ -51,20 +51,25 @@ if [ ${#MISSING_PACKAGES[@]} -gt 0 ]; then
     
     # Install packages automatically (no prompt)
     # Use apt directly if running as root, otherwise use sudo
+    PACKAGES_OK=true
     if [ "$EUID" -eq 0 ]; then
         apt update || echo "⚠ apt update failed, continuing anyway..."
         apt install -y "${MISSING_PACKAGES[@]}" || {
+            PACKAGES_OK=false
             echo "⚠ Package installation failed, but continuing with WiFi monitor setup"
             echo "  You may need to install packages manually: apt install -y ${MISSING_PACKAGES[*]}"
         }
     else
         sudo apt update || echo "⚠ apt update failed, continuing anyway..."
         sudo apt install -y "${MISSING_PACKAGES[@]}" || {
+            PACKAGES_OK=false
             echo "⚠ Package installation failed, but continuing with WiFi monitor setup"
             echo "  You may need to install packages manually: sudo apt install -y ${MISSING_PACKAGES[*]}"
         }
     fi
-    echo "✓ Package installation completed"
+    if [ "$PACKAGES_OK" = true ]; then
+        echo "✓ Package installation completed"
+    fi
 fi
 
 # Render the unit from systemd/ledmatrix-wifi-monitor.service rather than

scripts/install/lib_systemd_render.sh

@@ -2,9 +2,10 @@
 #
 # Shared helper for rendering systemd unit templates via sed.
 #
-# Sourced by install_service.sh, install_web_service.sh and
-# install_wifi_monitor.sh so all three escape sed replacement text the same
-# way instead of carrying three copies of the same fix.
+# Sourced by install_service.sh, install_web_service.sh,
+# install_wifi_monitor.sh, install_dns_fix.sh and install_mqtt_bridge.sh so
+# every unit renderer escapes sed replacement text the same way instead of
+# carrying its own copy of the fix.
 
 # sed_escape_replacement VALUE
 #

scripts/install/one-shot-install.sh

@@ -205,27 +205,6 @@ check_sudo() {
     print_success "Sudo access confirmed"
 }
 
-# Fix /tmp permissions if needed (common issue when running via curl | bash)
-# Note: /tmp permission fixing is now done inline before running first_time_install.sh
-# This function is kept for backward compatibility but not actively used
-fix_tmp_permissions() {
-    CURRENT_STEP="TMP directory check"
-    # Only fix if /tmp is actually not writable (don't preemptively fix)
-    if [ ! -w /tmp ]; then
-        print_warning "/tmp is not writable, attempting to fix..."
-        if [ "$EUID" -eq 0 ]; then
-            chmod 1777 /tmp 2>/dev/null || true
-        else
-            sudo chmod 1777 /tmp 2>/dev/null || true
-        fi
-    fi
-    
-    # Ensure TMPDIR is set correctly
-    if [ -z "${TMPDIR:-}" ] || [ ! -w "${TMPDIR:-/tmp}" ]; then
-        export TMPDIR=/tmp
-    fi
-}
-
 # Main installation function
 main() {
     print_step "LED Matrix One-Shot Installation"
@@ -429,6 +408,13 @@ main() {
         print_step "Installation Complete!"
         print_success "LED Matrix has been successfully installed!"
         echo ""
+        # first_time_install.sh -y reboots as its last action, so by now the
+        # reboot is under way (unless LEDMATRIX_SKIP_REBOOT_PROMPT=1 was set).
+        if [ "${LEDMATRIX_SKIP_REBOOT_PROMPT:-0}" != "1" ]; then
+            echo "The installer has just started a reboot to finish setup, so this"
+            echo "session may disconnect now. Give the Pi a few minutes to come back, then:"
+            echo ""
+        fi
         echo "Next steps:"
         echo "  1. Configure your settings: sudo nano $REPO_DIR/config/config.json"
         if command -v hostname >/dev/null 2>&1; then
@@ -449,7 +435,7 @@ main() {
         else
             echo "  2. Or use the web interface: http://<your-pi-ip>:5000"
         fi
-        echo "  3. Start the service: sudo systemctl start ledmatrix.service"
+        echo "  3. The display service starts on boot; to start it by hand: sudo systemctl start ledmatrix.service"
         echo ""
     else
         print_error "Main installation script exited with code $INSTALL_EXIT_CODE"