Nitpick comments

src/activities/reader/MdReaderActivity.cpp

@@ -616,7 +616,7 @@ bool MdReaderActivity::loadPageAtOffset(size_t offset, bool startInCodeBlock, st
       if (renderer.isSdCardFont(cachedFontId)) {
         std::string flatText;
         for (const auto& span : flatLine.spans) flatText += span.text;
-        renderer.ensureSdCardFontReady(cachedFontId, flatText.c_str());
+        if (!flatText.empty()) renderer.ensureSdCardFontReady(cachedFontId, flatText.c_str());
       }
 
       size_t linesBefore = outLines.size();

src/activities/reader/TxtReaderActivity.cpp

@@ -45,7 +45,9 @@ size_t parseAndWrapLines(const uint8_t* buffer, size_t chunkSize, size_t fileOff
     std::string line(reinterpret_cast<const char*>(buffer + pos), displayLen);
     size_t lineBytePos = 0;
 
-    renderer.ensureSdCardFontReady(fontId, line.c_str());
+    if (renderer.isSdCardFont(fontId) && !line.empty()) {
+      renderer.ensureSdCardFontReady(fontId, line.c_str());
+    }
 
     while (!line.empty() && static_cast<int>(outLines.size()) < linesPerPage) {
       if (renderer.getTextWidth(fontId, line.c_str()) <= vw) {