diff --git a/lib/Epub/Epub.cpp b/lib/Epub/Epub.cpp
index d1855cc..4040191 100644
--- a/lib/Epub/Epub.cpp
+++ b/lib/Epub/Epub.cpp
@@ -148,23 +148,55 @@ bool Epub::load() {
     return false;
   }
 
-  // determine size of spine items
-  size_t spineItemsCount = getSpineItemsCount();
-  size_t spineItemsSize = 0;
-  for (size_t i = 0; i < spineItemsCount; i++) {
-    std::string spineItem = getSpineItem(i);
-    size_t s = 0;
-    getItemSize(spineItem, &s);
-    spineItemsSize += s;
-    cumulativeSpineItemSize.emplace_back(spineItemsSize);
-  }
-  Serial.printf("[%lu] [EBP] Book size: %u\n", millis(), spineItemsSize);
-
+  initializeSpineItemSizes();
   Serial.printf("[%lu] [EBP] Loaded ePub: %s\n", millis(), filepath.c_str());
 
   return true;
 }
 
+void Epub::initializeSpineItemSizes(){
+
+    setupCacheDir();
+
+    size_t spineItemsCount = getSpineItemsCount();
+    size_t cumSpineItemSize = 0;
+    if (SD.exists((getCachePath() + "/spine_size.bin").c_str())) {
+      File f = SD.open((getCachePath() + "/spine_size.bin").c_str());
+      uint8_t data[4];
+      for (size_t i = 0; i < spineItemsCount; i++) {
+        f.read(data, 4);
+        cumSpineItemSize  = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
+        cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
+        // Serial.printf("[%lu] [EBP] Loading item %d size %u to %u %u\n", millis(),
+        //     i, cumSpineItemSize, data[1], data[0]);
+      }
+      f.close();
+    } else {
+        File f = SD.open((getCachePath() + "/spine_size.bin").c_str(), FILE_WRITE);
+        uint8_t data[4];
+        // determine size of spine items
+        for (size_t i = 0; i < spineItemsCount; i++) {
+          std::string spineItem = getSpineItem(i);
+          size_t s = 0;
+          getItemSize(spineItem, &s);
+          cumSpineItemSize += s;
+          cumulativeSpineItemSize.emplace_back(cumSpineItemSize);
+
+          // and persist to cache
+          data[0] = cumSpineItemSize & 0xFF;
+          data[1] = (cumSpineItemSize >> 8) & 0xFF;
+          data[2] = (cumSpineItemSize >> 16) & 0xFF;
+          data[3] = (cumSpineItemSize >> 24) & 0xFF;
+          // Serial.printf("[%lu] [EBP] Persisting item %d size %u to %u %u\n", millis(),
+          //     i, cumSpineItemSize, data[1], data[0]);
+          f.write(data, 4);
+        }
+
+        f.close();
+    }
+    Serial.printf("[%lu] [EBP] Book size: %lu\n", millis(), cumSpineItemSize);
+}
+
 bool Epub::clearCache() const {
   if (!SD.exists(cachePath.c_str())) {
     Serial.printf("[%lu] [EPB] Cache does not exist, no action needed\n", millis());
diff --git a/lib/Epub/Epub.h b/lib/Epub/Epub.h
index 1f2dfa9..f22b630 100644
--- a/lib/Epub/Epub.h
+++ b/lib/Epub/Epub.h
@@ -32,6 +32,7 @@ class Epub {
   bool findContentOpfFile(std::string* contentOpfFile) const;
   bool parseContentOpf(const std::string& contentOpfFilePath);
   bool parseTocNcxFile();
+  void initializeSpineItemSizes();
 
  public:
   explicit Epub(std::string filepath, const std::string& cacheDir) : filepath(std::move(filepath)) {