diff --git a/frontend/templates/index.html b/frontend/templates/index.html
index 5e41565..ede9020 100644
--- a/frontend/templates/index.html
+++ b/frontend/templates/index.html
@@ -69,9 +69,9 @@ function toggleSourceInput(e) {
 // ── Progress helpers ──────────────────────────────────────────────
 function setPhase(label, pct, isSpinner) {
   const el = document.getElementById('phase-label');
-  if (el) el.innerHTML = (isSpinner ? '<span class="spinner"></span> ' : '') + label;
   const fill = document.getElementById('progress-fill');
-  if (fill) { fill.style.width = pct + '%'; fill.textContent = pct > 0 ? pct + '%' : ''; }
+  console.log('[setPhase] el:', !!el, 'fill:', !!fill, 'label:', label, 'pct:', pct);
+  if (el) el.innerHTML = (isSpinner ? '<span class="spinner"></span> ' : '') + label;
 }
 
 function showError(msg) {
@@ -135,8 +135,8 @@ async function handleUpload(formData) {
     xhr.timeout = 7200000;  // 2 hour timeout for very large uploads
 
     xhr.upload.addEventListener('progress', (e) => {
+      console.log('[upload] progress', e.loaded, e.total, e.lengthComputable);
       if (e.lengthComputable) {
-        const pct = Math.round((e.loaded / e.total) * 100);
         setPhase('Uploading source file... ' + (e.loaded / (1024**3)).toFixed(1) + ' GiB', pct, false);
       } else {
         // Fallback: show bytes uploaded even without total
@@ -145,6 +145,7 @@ async function handleUpload(formData) {
     });
 
     xhr.addEventListener('loadstart', () => {
+      console.log('[upload] loadstart');
       setPhase('Uploading source file...', 0, true);
     });