diff --git a/frontend/src/app/main/data/viewer.cljs b/frontend/src/app/main/data/viewer.cljs
index 87b9c1007b..1d9c49f9d3 100644
--- a/frontend/src/app/main/data/viewer.cljs
+++ b/frontend/src/app/main/data/viewer.cljs
@@ -222,7 +222,12 @@
     (watch [_ state _]
       (if (and (features/active-feature? state "render-wasm/v1")
                (contains? cf/flags :available-viewer-wasm))
-        (let [objects (dsh/lookup-page-objects state file-id page-id)
+        ;; Fallback matches the viewer UI when the URL omits page-id.
+        (let [page-id (or page-id
+                          (-> (dsh/lookup-file-data state file-id)
+                              :pages
+                              first))
+              objects (dsh/lookup-page-objects state file-id page-id)
 
               shapes
               (reduce-kv
@@ -233,13 +238,12 @@
                []
                objects)
 
-              ;; Creates a stream from the async callback. This stream will only
-              ;; emit one single value after the objects have finished loading
-              ;; in the wasm memory.
+              ;; Positive size required: OffscreenCanvas(0, 0) crashes
+              ;; `_set_render_options` on some browsers.
               set-objects-stream
               (rx/create
                (fn [subs]
-                 (wasm.api/init-canvas-context (js/OffscreenCanvas. 0 0))
+                 (wasm.api/init-canvas-context (js/OffscreenCanvas. 64 64))
                  (wasm.api/set-objects-callback shapes #(rx/push! subs :done))
                  nil))]
 
diff --git a/frontend/src/app/render_wasm/api.cljs b/frontend/src/app/render_wasm/api.cljs
index a96353dea4..388c3611d7 100644
--- a/frontend/src/app/render_wasm/api.cljs
+++ b/frontend/src/app/render_wasm/api.cljs
@@ -2175,6 +2175,9 @@
           browser (sr/translate-browser cf/browser)
           dpr     (get-dpr)
           [css-w css-h] (canvas-css-size canvas dpr)
+          ;; Avoid 0×0 Skia/GL surfaces (crashes on some browsers).
+          css-w (mth/max 1 css-w)
+          css-h (mth/max 1 css-h)
           can-listen? (fn? (.-addEventListener ^js canvas))]
       (when-not (nil? context)
         (let [handle (.registerContext ^js gl context #js {"majorVersion" 2})]