diff --git a/qml/pages/BookDetailPage.qml b/qml/pages/BookDetailPage.qml
index 15948da..328fb88 100644
--- a/qml/pages/BookDetailPage.qml
+++ b/qml/pages/BookDetailPage.qml
@@ -122,15 +122,25 @@ Page {
             return u
         var base = appSettings.baseUrl
         // il server dietro sottopath (es. /calibre) emette link che lo includono già:
-        // evita di raddoppiarlo
-        var basePath = base.replace(/^https?:\/\/[^\/]+/, "")
+        // evita di raddoppiarlo (solo operazioni su stringhe, niente regex)
+        var schemeEnd = base.indexOf("://")
+        var slash = base.indexOf("/", schemeEnd + 3)
+        var basePath = slash >= 0 ? base.substring(slash) : ""
         if (basePath.length > 1 && u.indexOf(basePath) === 0)
             return base + u.substring(basePath.length)
         return base + (u.charAt(0) === "/" ? u : "/" + u)
     }
 
     function sanitizeFileName(s) {
-        return s.replace(/[\\/:*?"<>|]/g, "_").replace(/\s+/g, " ").trim()
+        var out = ""
+        for (var i = 0; i < s.length; i++) {
+            var c = s.charAt(i)
+            if (c === '/' || c === ':' || c === '*' || c === '?' || c === '"' || c === '<' || c === '>' || c === '|' || c.charCodeAt(0) === 92)
+                out += '_'
+            else
+                out += c
+        }
+        return out.trim()
     }
 
     function startDownload(format) {