diff --git a/web/src/index.html b/web/src/index.html
index 4ea2d49..ea0be03 100644
--- a/web/src/index.html
+++ b/web/src/index.html
@@ -41,13 +41,13 @@
         </header>
 
         <!-- Shown until JS initialises -->
-        <div id="initial-loader" class="initial-loader">
-            <div class="spinner"></div>
+        <div id="initial-loader" class="initial-loader" role="status" aria-label="Loading">
+            <div class="spinner" aria-hidden="true"></div>
             <p>Loading&hellip;</p>
         </div>
 
         <!-- Step indicator (populated dynamically by app.js) -->
-        <nav id="step-nav" class="step-nav" hidden>
+        <nav id="step-nav" class="step-nav" aria-label="Progress" hidden>
             <ol></ol>
         </nav>
 
@@ -89,13 +89,13 @@
             <p class="fallback-hint">
                 <strong>Select the version number currently installed on your device.</strong> If it does not appear in this list, your software version is not supported for custom patching. You can go back and choose NickelMenu instead, which works with all versions.
             </p>
-            <select id="manual-version">
+            <select id="manual-version" aria-label="Software version">
                 <option value="">-- Select software version --</option>
             </select>
             <p id="manual-version-hint" class="fallback-hint">
                 You can find the version number on your Kobo under <strong>More &gt; Settings &gt; Device information</strong> &gt; <strong>Software version</strong>.
             </p>
-            <select id="manual-model" hidden>
+            <select id="manual-model" aria-label="Kobo model" hidden>
                 <option value="">-- Select your Kobo model --</option>
             </select>
             <p id="manual-model-hint" class="fallback-hint" hidden>
@@ -142,7 +142,7 @@
         <!-- Step 2: Mode selection -->
         <section id="step-mode" class="step" hidden>
             <p>What would you like to do?</p>
-            <div class="mode-cards">
+            <div class="mode-cards" role="radiogroup" aria-label="Mode selection">
                 <label class="mode-card mode-card-selected">
                     <input type="radio" name="mode" value="nickelmenu" checked>
                     <div class="mode-card-body">
@@ -168,7 +168,7 @@
         <!-- Step 2b: NickelMenu configuration -->
         <section id="step-nickelmenu" class="step" hidden>
             <p>Choose what to do with your Kobo.</p>
-            <div class="nm-options">
+            <div class="nm-options" role="radiogroup" aria-label="NickelMenu options">
                 <label class="nm-option">
                     <input type="radio" name="nm-option" value="preset">
                     <div class="nm-option-body">
@@ -224,8 +224,8 @@
 
         <!-- NickelMenu installing -->
         <section id="step-nm-installing" class="step" hidden>
-            <div class="build-header">
-                <div class="spinner"></div>
+            <div class="build-header" role="status" aria-live="polite">
+                <div class="spinner" aria-hidden="true"></div>
                 <p id="nm-progress">Starting...</p>
             </div>
         </section>
@@ -293,8 +293,8 @@
 
         <!-- Step 4: Building -->
         <section id="step-building" class="step" hidden>
-            <div class="build-header">
-                <div class="spinner"></div>
+            <div class="build-header" role="status" aria-live="polite">
+                <div class="spinner" aria-hidden="true"></div>
                 <p id="build-progress">Starting...</p>
             </div>
             <pre id="build-log" class="build-log"></pre>
@@ -362,10 +362,10 @@
         </p>
     </footer>
 
-    <dialog id="how-it-works-dialog" class="modal">
+    <dialog id="how-it-works-dialog" class="modal" aria-labelledby="how-it-works-title">
         <div class="modal-content">
             <div class="modal-header">
-                <h2>Disclaimer</h2>
+                <h2 id="how-it-works-title">Disclaimer</h2>
                 <button id="btn-close-dialog" class="modal-close" aria-label="Close">&times;</button>
             </div>
             <div class="modal-body">
@@ -425,10 +425,10 @@
         </div>
     </dialog>
 
-    <dialog id="privacy-dialog" class="modal">
+    <dialog id="privacy-dialog" class="modal" aria-labelledby="privacy-title">
         <div class="modal-content">
             <div class="modal-header">
-                <h2>Privacy</h2>
+                <h2 id="privacy-title">Privacy</h2>
                 <button id="btn-close-privacy" class="modal-close" aria-label="Close">&times;</button>
             </div>
             <div class="modal-body">
diff --git a/web/src/js/app.js b/web/src/js/app.js
index 4fbdf7f..7baeda1 100644
--- a/web/src/js/app.js
+++ b/web/src/js/app.js
@@ -181,8 +181,12 @@ import JSZip from 'jszip';
         items.forEach((li, i) => {
             const stepNum = i + 1;
             li.classList.remove('active', 'done');
+            li.removeAttribute('aria-current');
             if (stepNum < num) li.classList.add('done');
-            else if (stepNum === num) li.classList.add('active');
+            else if (stepNum === num) {
+                li.classList.add('active');
+                li.setAttribute('aria-current', 'step');
+            }
         });
         stepNav.hidden = false;
     }
@@ -746,13 +750,13 @@ import JSZip from 'jszip';
                 nmProgress.textContent = 'Removing NickelMenu assets...';
                 try {
                     await device.removeEntry(['.adds', 'nm'], { recursive: true });
-                } catch {
-                    // ignore — folder may already be gone
+                } catch (err) {
+                    console.warn('Could not remove .adds/nm:', err);
                 }
                 try {
                     await device.removeEntry(['.adds', 'scripts'], { recursive: true });
-                } catch {
-                    // ignore — folder may already be gone
+                } catch (err) {
+                    console.warn('Could not remove .adds/scripts:', err);
                 }
                 nmProgress.textContent = 'Creating uninstall marker...';
                 await device.writeFile(['.adds', 'nm', 'uninstall'], new Uint8Array(0));
@@ -763,8 +767,8 @@ import JSZip from 'jszip';
                     for (const entry of feature.uninstall.paths) {
                         try {
                             await device.removeEntry(entry.path, { recursive: !!entry.recursive });
-                        } catch {
-                            // ignore — file may already be gone
+                        } catch (err) {
+                            console.warn(`Could not remove ${entry.path.join('/')}:`, err);
                         }
                     }
                 }
diff --git a/web/src/js/kobo-device.js b/web/src/js/kobo-device.js
index 8b0b971..c6f7609 100644
--- a/web/src/js/kobo-device.js
+++ b/web/src/js/kobo-device.js
@@ -62,18 +62,20 @@ class KoboDevice {
         let koboDir;
         try {
             koboDir = await this.directoryHandle.getDirectoryHandle('.kobo');
-        } catch {
+        } catch (err) {
             throw new Error(
-                'This does not appear to be a Kobo device. Could not find the .kobo directory.'
+                'This does not appear to be a Kobo device. Could not find the .kobo directory.',
+                { cause: err }
             );
         }
 
         let versionFile;
         try {
             versionFile = await koboDir.getFileHandle('version');
-        } catch {
+        } catch (err) {
             throw new Error(
-                'Could not find .kobo/version. Is this the root of your Kobo drive?'
+                'Could not find .kobo/version. Is this the root of your Kobo drive?',
+                { cause: err }
             );
         }
 
diff --git a/web/src/js/patch-ui.js b/web/src/js/patch-ui.js
index 664fd9a..d75e13c 100644
--- a/web/src/js/patch-ui.js
+++ b/web/src/js/patch-ui.js
@@ -155,7 +155,8 @@ async function scanAvailablePatches() {
             }
         }
         return result;
-    } catch {
+    } catch (err) {
+        console.error('Failed to load patch index:', err);
         return [];
     }
 }