diff --git a/frontend/js/main.js b/frontend/js/main.js
index 790f3fd..620e29f 100644
--- a/frontend/js/main.js
+++ b/frontend/js/main.js
@@ -1880,7 +1880,7 @@ function showChznScanModal(onSaved) {
     </div>`;
   document.body.appendChild(ov);
 
-  let stream = null, scanning = false, busy = false;
+  let stream = null, scanning = false, busy = false, zoomFactor = 1;
   let base = winStack.length;
   let statusEl = ov.querySelector("#cz-status");
   let video = ov.querySelector("#cz-video");
@@ -1902,6 +1902,22 @@ function showChznScanModal(onSaved) {
     _skipPops = count;
     if (count > 0) history.go(-count);
   }
+  // Close this modal AND wait for its history.go popstate(s) to flush before the
+  // caller opens the next modal. Opening it synchronously after close() races the
+  // async history.go (it would unwind the NEW modal's entry) and desyncs the back
+  // stack — that was the "swipe-back does nothing" bug on scan -> add-product.
+  function closeThen() {
+    let count = winStack.length - base;
+    for (let i = 0; i < count; i++) winStack.pop().close();
+    if (count <= 0) return Promise.resolve();
+    _skipPops = count;
+    return new Promise(res => {
+      let remaining = count;
+      let h = () => { if (--remaining <= 0) { window.removeEventListener("popstate", h); res(); } };
+      window.addEventListener("popstate", h);
+      history.go(-count);
+    });
+  }
 
   async function onDecoded(rawVal) {
     if (busy) return;
@@ -1910,7 +1926,7 @@ function showChznScanModal(onSaved) {
     try {
       let prefill = await ChZ.resolve(rawVal);
       stopCamera();
-      close();
+      await closeThen();
       showAddProductModal(onSaved, prefill);
     } catch (e) {
       busy = false;
@@ -1929,9 +1945,9 @@ function showChznScanModal(onSaved) {
     // sample exactly that center square (WYSIWYG). zxing-wasm locates the code
     // anywhere within it — no need for the user to fill a tiny box; use zoom to
     // enlarge the code at a focusable distance instead.
-    let side = Math.min(vw, vh);
+    let side = Math.min(vw, vh) / zoomFactor; // digital zoom crops tighter to center
     let sx = (vw - side) / 2, sy = (vh - side) / 2;
-    let out = Math.min(side, 768); // enough detail, still fast
+    let out = Math.min(Math.min(vw, vh), 768); // enough detail, still fast
     canvas.width = out; canvas.height = out;
     cctx.drawImage(video, sx, sy, side, side, 0, 0, out, out);
     return cctx.getImageData(0, 0, out, out);
@@ -1963,16 +1979,25 @@ function showChznScanModal(onSaved) {
         track.applyConstraints({ advanced: [{ focusMode: "continuous" }] }).catch(() => {});
       }
     } catch {}
+    // Zoom slider: prefer hardware zoom; otherwise fall back to digital zoom
+    // (CSS-scale the preview + crop the decode ROI). Always shown so the user can
+    // enlarge a small code instead of moving the phone inside its focus range.
+    let zw = ov.querySelector("#cz-zoom-wrap");
+    let zi = ov.querySelector("#cz-zoom");
     if (caps.zoom && caps.zoom.max > caps.zoom.min) {
-      let zw = ov.querySelector("#cz-zoom-wrap");
-      let zi = ov.querySelector("#cz-zoom");
       zi.min = caps.zoom.min; zi.max = caps.zoom.max;
       zi.step = caps.zoom.step || (caps.zoom.max - caps.zoom.min) / 100 || 0.1;
-      let cur = ((track.getSettings && track.getSettings()) || {}).zoom;
-      zi.value = cur || caps.zoom.min;
+      zi.value = ((track.getSettings && track.getSettings()) || {}).zoom || caps.zoom.min;
       zi.oninput = () => { track.applyConstraints({ advanced: [{ zoom: parseFloat(zi.value) }] }).catch(() => {}); };
-      zw.style.display = "flex";
+    } else {
+      zi.min = 1; zi.max = 5; zi.step = 0.1; zi.value = 1;
+      zi.oninput = () => {
+        zoomFactor = parseFloat(zi.value) || 1;
+        video.style.transformOrigin = "center center";
+        video.style.transform = "scale(" + zoomFactor + ")";
+      };
     }
+    zw.style.display = "flex";
     if (caps.torch) {
       let tb = ov.querySelector("#cz-torch");
       tb.style.display = "block";