diff --git a/scripts/install/server.sh b/scripts/install/server.sh
index f85341e..d63917b 100755
--- a/scripts/install/server.sh
+++ b/scripts/install/server.sh
@@ -51,6 +51,121 @@ read_existing_hdmi_connector() {
   normalize_hdmi_connector "$value"
 }
 
+boot_config_path() {
+  for path in /boot/config.txt /boot/firmware/config.txt; do
+    if [[ -e $path ]]; then
+      printf '%s\n' "$path"
+      return 0
+    fi
+  done
+  return 0
+}
+
+boot_cmdline_path() {
+  for path in /boot/cmdline.txt /boot/firmware/cmdline.txt; do
+    if [[ -e $path ]]; then
+      printf '%s\n' "$path"
+      return 0
+    fi
+  done
+  return 0
+}
+
+runtime_forced_hdmi_connectors() {
+  [[ -r /proc/cmdline ]] || return 0
+  tr ' ' '\n' </proc/cmdline |
+    sed -n 's/^video=\(HDMI-A-[0-9]\+\):.*e$/\1/p' |
+    sort -u
+}
+
+remove_lesavka_hdmi_config_force() {
+  local cfg tmp
+  cfg=$(boot_config_path)
+  [[ -n $cfg ]] || return 0
+  tmp=$(mktemp)
+  awk '
+    /^# lesavka: force HDMI/ {next}
+    /^hdmi_force_hotplug:[0-9]+=1$/ {next}
+    /^hdmi_group:[0-9]+=2$/ {next}
+    /^hdmi_mode:[0-9]+=82$/ {next}
+    {print}
+  ' "$cfg" >"$tmp"
+  sudo install -m 0644 "$tmp" "$cfg"
+  rm -f "$tmp"
+}
+
+write_hdmi_cmdline_force() {
+  local connector="${1:-}" cmd token tmp line
+  cmd=$(boot_cmdline_path)
+  [[ -n $cmd ]] || return 0
+  tmp=$(mktemp)
+  line=$(cat "$cmd")
+  for token in $line; do
+    case "$token" in
+      video=HDMI-A-*:1920x1080@60e)
+        continue
+        ;;
+    esac
+    printf '%s ' "$token" >>"$tmp"
+  done
+  if [[ -n $connector ]]; then
+    printf 'video=%s:1920x1080@60e ' "$connector" >>"$tmp"
+  fi
+  sed -i 's/[[:space:]]*$//' "$tmp"
+  printf '\n' >>"$tmp"
+  sudo install -m 0644 "$tmp" "$cmd"
+  rm -f "$tmp"
+}
+
+clear_lesavka_hdmi_boot_force() {
+  remove_lesavka_hdmi_config_force
+  write_hdmi_cmdline_force ""
+}
+
+write_hdmi_boot_force() {
+  local connector="$1" idx cfg
+  connector=$(normalize_hdmi_connector "$connector")
+  if [[ ! $connector =~ ^HDMI-A-([0-9]+)$ ]]; then
+    echo "⚠️  cannot write HDMI boot force for unexpected connector '$connector'." >&2
+    return 0
+  fi
+
+  idx=$((BASH_REMATCH[1] - 1))
+  cfg=$(boot_config_path)
+  remove_lesavka_hdmi_config_force
+  if [[ -n $cfg ]]; then
+    {
+      echo
+      echo "# lesavka: force HDMI mode for capture dongle ($connector)"
+      printf 'hdmi_force_hotplug:%s=1\n' "$idx"
+      printf 'hdmi_group:%s=2\n' "$idx"
+      printf 'hdmi_mode:%s=82\n' "$idx"
+    } | sudo tee -a "$cfg" >/dev/null
+  fi
+  write_hdmi_cmdline_force "$connector"
+}
+
+prepare_hdmi_detection_boot_state() {
+  local -a forced=()
+
+  if [[ -n ${LESAVKA_HDMI_CONNECTOR:-} ]]; then
+    return 0
+  fi
+
+  mapfile -t forced < <(runtime_forced_hdmi_connectors)
+  if (( ${#forced[@]} <= 1 )); then
+    return 0
+  fi
+
+  echo "⚠️  current boot forces multiple HDMI connectors: ${forced[*]}" >&2
+  echo "    Linux will report every forced connector as connected, so auto-detection cannot be trusted yet." >&2
+  clear_lesavka_hdmi_boot_force
+  echo "✅  removed Lesavka-managed dual-HDMI force settings from boot config." >&2
+  echo "    Reboot Theia, then rerun this installer so it can see the real connected HDMI port." >&2
+  echo "    If both ports are physically connected after reboot, rerun once with LESAVKA_HDMI_CONNECTOR=HDMI-A-N." >&2
+  exit 1
+}
+
 describe_hdmi_connectors() {
   local dev name status id
   for dev in /sys/class/drm/card*-HDMI-A-*; do
@@ -191,6 +306,7 @@ echo "==> 2a. Kernel-driver tweaks"
 cat <<'EOF' | sudo tee /etc/modprobe.d/gc311-stream.conf >/dev/null
 options uvcvideo quirks=0x200 timeout=10000
 EOF
+prepare_hdmi_detection_boot_state
 
 echo "==> 2b. Predictable /dev names for each capture card"
 # ensure relay (GPIO power) is on if present
@@ -298,6 +414,7 @@ sudo install -d -m 0755 /etc/lesavka
 HDMI_CONNECTOR=$(resolve_hdmi_connector)
 if [[ -n $HDMI_CONNECTOR ]]; then
   echo "   ↪ HDMI connector: $HDMI_CONNECTOR"
+  write_hdmi_boot_force "$HDMI_CONNECTOR"
 else
   echo "⚠️  no connected HDMI connector detected; leaving LESAVKA_HDMI_CONNECTOR unset." >&2
 fi