diff --git a/src-tauri/src/commands.rs b/src-tauri/src/commands.rs
index c03a535..47bedb7 100644
--- a/src-tauri/src/commands.rs
+++ b/src-tauri/src/commands.rs
@@ -829,11 +829,13 @@ pub async fn read_tiff_preview_png(path: String) -> Result<String, String> {
     Ok(base64::engine::general_purpose::STANDARD.encode(png_bytes.into_inner()))
 }
 
-#[derive(Debug, Deserialize, Serialize)]
+#[derive(Debug, Deserialize, Serialize, Clone)]
 pub struct ChartreadConfig {
     pub basename: String,
     pub cwd: String,
     pub port: Option<String>,
+    #[serde(default)]
+    pub enable_i1pro2_leds: Option<bool>,
 }
 
 pub fn build_chartread_args(config: &ChartreadConfig) -> Vec<String> {
@@ -849,6 +851,11 @@ pub fn build_chartread_args(config: &ChartreadConfig) -> Vec<String> {
         }
     }
 
+    if config.enable_i1pro2_leds.unwrap_or(false) {
+        args.push("-Y".to_string());
+        args.push("l".to_string());
+    }
+
     args.push(config.basename.clone());
     args
 }
@@ -857,8 +864,12 @@ pub fn build_chartread_args(config: &ChartreadConfig) -> Vec<String> {
 pub async fn run_chartread(
     app: AppHandle,
     state: State<'_, ProcessManager>,
-    config: ChartreadConfig,
+    mut config: ChartreadConfig,
 ) -> Result<(), String> {
+    if config.enable_i1pro2_leds.is_none() {
+        let settings = crate::settings::load_settings(app.clone()).unwrap_or_default();
+        config.enable_i1pro2_leds = Some(settings.enable_i1pro2_leds);
+    }
     let binary = resolve_binary(app.clone(), "chartread".to_string()).await?;
     let args = build_chartread_args(&config);
     let id = format!("chartread_{}", config.basename);
@@ -1558,6 +1569,7 @@ mod tests {
             basename: "my_profile".to_string(),
             cwd: "/home/user".to_string(),
             port: None,
+            enable_i1pro2_leds: None,
         };
         let args = build_chartread_args(&config);
         assert_eq!(args, vec!["-v", "-u", "my_profile"]);
@@ -1569,6 +1581,7 @@ mod tests {
             basename: "my_profile".to_string(),
             cwd: "/home/user".to_string(),
             port: Some("".to_string()),
+            enable_i1pro2_leds: None,
         };
         let args = build_chartread_args(&config);
         assert_eq!(args, vec!["-v", "-u", "my_profile"]);
@@ -1580,11 +1593,48 @@ mod tests {
             basename: "my_profile".to_string(),
             cwd: "/home/user".to_string(),
             port: Some("1".to_string()),
+            enable_i1pro2_leds: None,
         };
         let args = build_chartread_args(&config);
         assert_eq!(args, vec!["-v", "-u", "-c", "1", "my_profile"]);
     }
 
+    #[test]
+    fn test_build_chartread_args_leds_enabled() {
+        let config = ChartreadConfig {
+            basename: "my_profile".to_string(),
+            cwd: "/home/user".to_string(),
+            port: None,
+            enable_i1pro2_leds: Some(true),
+        };
+        let args = build_chartread_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "-Y", "l", "my_profile"]);
+    }
+
+    #[test]
+    fn test_build_chartread_args_with_port_and_leds() {
+        let config = ChartreadConfig {
+            basename: "my_profile".to_string(),
+            cwd: "/home/user".to_string(),
+            port: Some("1".to_string()),
+            enable_i1pro2_leds: Some(true),
+        };
+        let args = build_chartread_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "-c", "1", "-Y", "l", "my_profile"]);
+    }
+
+    #[test]
+    fn test_build_chartread_args_leds_disabled() {
+        let config = ChartreadConfig {
+            basename: "my_profile".to_string(),
+            cwd: "/home/user".to_string(),
+            port: None,
+            enable_i1pro2_leds: Some(false),
+        };
+        let args = build_chartread_args(&config);
+        assert_eq!(args, vec!["-v", "-u", "my_profile"]);
+    }
+
     #[test]
     fn test_build_average_args() {
         let config = AverageConfig {
diff --git a/src-tauri/src/settings.rs b/src-tauri/src/settings.rs
index 3716434..192a8e6 100644
--- a/src-tauri/src/settings.rs
+++ b/src-tauri/src/settings.rs
@@ -74,6 +74,8 @@ pub struct AppSettings {
     pub delta_e_warning_max: f64,
     #[serde(default)]
     pub custom_presets: Vec<ProfilingPreset>,
+    #[serde(default)]
+    pub enable_i1pro2_leds: bool,
 }
 
 impl Default for AppSettings {
@@ -85,6 +87,7 @@ impl Default for AppSettings {
             delta_e_good_max: default_delta_e_good_max(),
             delta_e_warning_max: default_delta_e_warning_max(),
             custom_presets: Vec::new(),
+            enable_i1pro2_leds: false,
         }
     }
 }
@@ -466,4 +469,28 @@ mod tests {
             assert_eq!(parse_log_level_filter(Some("unknown")), log::LevelFilter::Info);
         }
     }
+
+    #[test]
+    fn test_default_enable_i1pro2_leds() {
+        let settings = AppSettings::default();
+        assert_eq!(settings.enable_i1pro2_leds, false);
+    }
+
+    #[test]
+    fn test_enable_i1pro2_leds_serialization() {
+        // Missing field defaults to false
+        let json_empty = "{}";
+        let settings_empty: AppSettings = serde_json::from_str(json_empty).unwrap();
+        assert_eq!(settings_empty.enable_i1pro2_leds, false);
+
+        // Explicit true
+        let json_true = r#"{"enable_i1pro2_leds": true}"#;
+        let settings_true: AppSettings = serde_json::from_str(json_true).unwrap();
+        assert_eq!(settings_true.enable_i1pro2_leds, true);
+
+        // Explicit false
+        let json_false = r#"{"enable_i1pro2_leds": false}"#;
+        let settings_false: AppSettings = serde_json::from_str(json_false).unwrap();
+        assert_eq!(settings_false.enable_i1pro2_leds, false);
+    }
 }
diff --git a/src/index.html b/src/index.html
index df05b8d..68bf9e2 100644
--- a/src/index.html
+++ b/src/index.html
@@ -883,9 +883,19 @@
           <label for="argyll_binary_dir">ArgyllCMS Binary Directory Override</label>
           <input type="text" id="argyll_binary_dir" placeholder="Leave empty for bundled sidecars (e.g. /usr/bin)">
         </div>
-        <div class="form-group">
-          <label for="default_instrument">Default Instrument Override</label>
-          <input type="text" id="default_instrument" placeholder="e.g. i1">
+        <div class="form-group" style="margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border-color, #333);">
+          <label style="font-weight: 600;">Instrument &amp; Measurement Preferences</label>
+          <div style="margin-top: 8px;">
+            <label for="default_instrument" class="sub-label">Default Instrument Override</label>
+            <input type="text" id="default_instrument" placeholder="e.g. i1">
+          </div>
+          <div style="margin-top: 12px;">
+            <label class="checkbox-label" for="enable_i1pro2_leds" style="display: flex; align-items: center; gap: 8px; cursor: pointer;">
+              <input type="checkbox" id="enable_i1pro2_leds">
+              <span>Enable i1Pro 2 status LEDs (<code>-Y l</code>)</span>
+            </label>
+            <small class="help-hint" style="display:block; font-size:0.75rem; color:var(--text-muted, #888); margin-top:3px;">Provides visual status feedback via the instrument ring LEDs during patch reading. Requires patched ArgyllCMS build.</small>
+          </div>
         </div>
         <div class="form-group" style="margin-top: 16px; padding-top: 14px; border-top: 1px solid var(--border-color, #333);">
           <label style="font-weight: 600;">Stage 3 ΔE₀₀ Traffic-Light Thresholds</label>
diff --git a/src/js/chartread.js b/src/js/chartread.js
index bbcca0f..3b8158c 100644
--- a/src/js/chartread.js
+++ b/src/js/chartread.js
@@ -426,8 +426,11 @@ export function initChartread() {
           }
         });
 
+        let lastStderrLine = "";
+
         const unlistenStderr = await listen("process:stderr", (event) => {
           if (event.payload.id === currentProcessId && event.payload.line) {
+            lastStderrLine = event.payload.line;
             logPre.textContent += "ERR: " + event.payload.line + "\n";
             logPre.scrollTop = logPre.scrollHeight;
           }
@@ -471,8 +474,10 @@ export function initChartread() {
             }
           } else {
             setState(STATE.FINISHED);
-            setPrompt(`❌ chartread exited with code ${event.payload.code}.`);
-            logPre.textContent += `\n[ERROR] chartread exited with code ${event.payload.code}.\n`;
+            if (logContainer) logContainer.open = true;
+            const errDetail = lastStderrLine ? ` (${lastStderrLine})` : "";
+            setPrompt(`❌ chartread exited with code ${event.payload.code}.${errDetail}`);
+            logPre.textContent += `\n[ERROR] chartread exited with code ${event.payload.code}.${errDetail}\n`;
           }
 
           setMeasurementBusy(false);
diff --git a/src/js/settings.js b/src/js/settings.js
index a54ab94..5dbe5de 100644
--- a/src/js/settings.js
+++ b/src/js/settings.js
@@ -21,6 +21,7 @@ export async function initSettings() {
     const deltaEGoodMax = document.getElementById('deltaEGoodMax');
     const deltaEWarningMax = document.getElementById('deltaEWarningMax');
     const deltaEThresholdError = document.getElementById('deltaEThresholdError');
+    const enableI1Pro2Leds = document.getElementById('enable_i1pro2_leds');
 
     if (!dialog || !openBtn) return;
 
@@ -57,6 +58,9 @@ export async function initSettings() {
             const settings = await invoke('load_settings');
             document.getElementById('argyll_binary_dir').value = settings.argyll_binary_dir || '';
             document.getElementById('default_instrument').value = settings.default_instrument || '';
+            if (enableI1Pro2Leds) {
+                enableI1Pro2Leds.checked = Boolean(settings.enable_i1pro2_leds);
+            }
             if (logLevelSelect && settings.log_level) {
                 logLevelSelect.value = settings.log_level;
             }
@@ -145,6 +149,7 @@ export async function initSettings() {
                     log_level: logLevelSelect ? logLevelSelect.value : (currentSettings.log_level || 'info'),
                     delta_e_good_max: getInputValueAsFloat('deltaEGoodMax', 2.0),
                     delta_e_warning_max: getInputValueAsFloat('deltaEWarningMax', 5.0),
+                    enable_i1pro2_leds: enableI1Pro2Leds ? enableI1Pro2Leds.checked : false,
                 };
                 await invoke('save_settings', { settings });
                 logger.info(`Settings saved. Log level set to: ${settings.log_level}`, 'Settings');