diff --git a/modules/rntuple.mjs b/modules/rntuple.mjs
index 939647eb6..fe29976ec 100644
--- a/modules/rntuple.mjs
+++ b/modules/rntuple.mjs
@@ -922,27 +922,37 @@ async function readHeaderFooter(tuple) {
    });
 }
 
-function readEntry(rntuple, fieldName, entryIndex) {
+function readEntry(rntuple, fieldName, clusterIndex, entryIndex) {
    const builder = rntuple.builder,
          field = builder.fieldDescriptors.find(f => f.fieldName === fieldName),
-         fieldData = rntuple._clusterData[fieldName];
+         columns = rntuple.fieldToColumns[fieldName];
 
    if (!field)
       throw new Error(`No descriptor for field ${fieldName}`);
-   if (!fieldData)
-      throw new Error(`No data for field ${fieldName}`);
+   if (!columns)
+      throw new Error(`No columns field ${fieldName}`);
 
-   // Detect and decode string fields
-   if (Array.isArray(fieldData) && fieldData.length === 2) {
-      const [offsets, payload] = fieldData,
-            start = entryIndex === 0 ? 0 : Number(offsets[entryIndex - 1]),
-            end = Number(offsets[entryIndex]),
-            decoded = payload.slice(start, end).join(''); // Convert to string
-      return decoded;
+
+   const pages = builder.pageLocations[clusterIndex]?.[columns[0].index]?.pages;
+   if (!pages)
+      throw new Error(`No pages found ${fieldName}`);
+
+   let pageid = 0;
+   while ((pageid < pages.length - 1) && (entryIndex >= Number(pages[pageid].numElements))) {
+      entryIndex -= Number(pages[pageid].numElements);
+      pageid++;
    }
 
-   // Fallback: primitive type (e.g. int, float)
-   return fieldData[0][entryIndex];
+   if (field.typeName === 'std::string') {
+      // string extracted from two columns
+      const offsets = rntuple._clusterData[columns[0].index][pageid],
+            payload = rntuple._clusterData[columns[1].index][pageid],
+            start = entryIndex === 0 ? 0 : Number(offsets[entryIndex - 1]),
+            end = Number(offsets[entryIndex]);
+      return payload.slice(start, end).join(''); // Convert to string
+   }
+   const values = rntuple._clusterData[columns[0].index];
+   return values[pageid][entryIndex];
 }
 
 /** @summary Return field name for specified branch index
@@ -953,11 +963,11 @@ function getSelectorFieldName(selector, i) {
 }
 
 // Read and process the next data cluster from the RNTuple
-function readNextCluster(rntuple, selector) {
+async function readNextCluster(rntuple, selector) {
    const builder = rntuple.builder;
 
    // Add validation
-   if (!builder.clusterSummaries || builder.clusterSummaries.length === 0)
+   if (!builder.clusterSummaries)
       throw new Error('No cluster summaries available - possibly incomplete file reading');
 
    const clusterIndex = selector.currentCluster,
@@ -967,6 +977,11 @@ function readNextCluster(rntuple, selector) {
       // Collect only selected field names from selector
          selectedFields = [];
 
+   if (!clusterSummary) {
+      selector.Terminate(clusterIndex > 0);
+      return false;
+   }
+
    for (let i = 0; i < selector.numBranches(); ++i)
       selectedFields.push(getSelectorFieldName(selector, i));
 
@@ -993,7 +1008,7 @@ function readNextCluster(rntuple, selector) {
    // Early exit if no pages to read (i.e., no selected fields matched)
    if (pages.length === 0) {
       selector.Terminate(false);
-      return Promise.resolve();
+      return false;
    }
 
    // Build flat array of [offset, size, offset, size, ...] to read pages
@@ -1040,68 +1055,35 @@ function readNextCluster(rntuple, selector) {
             });
 
       return Promise.all(unzipPromises).then(unzipBlobs => {
-         rntuple._clusterData = {}; // store deserialized data per field
+         rntuple._clusterData = {}; // store deserialized data per column index
 
          for (let i = 0; i < unzipBlobs.length; ++i) {
             const blob = unzipBlobs[i];
             // Ensure blob is a DataView
             if (!(blob instanceof DataView))
                throw new Error(`Invalid blob type for page ${i}: ${Object.prototype.toString.call(blob)}`);
-            const {
-               page,
-               colDesc
-            } = pages[i],
-                  field = builder.fieldDescriptors[colDesc.fieldId],
-                  values = builder.deserializePage(blob, colDesc, page);
+            const colDesc = pages[i].colDesc,
+                  values = builder.deserializePage(blob, colDesc, pages[i].page);
 
             // Support multiple representations (e.g., string fields with offsets + payload)
-            if (!rntuple._clusterData[field.fieldName])
-               rntuple._clusterData[field.fieldName] = [];
-
-            // splitting string fields into offset and payload components
-            if (field.typeName === 'std::string') {
-               if (
-                  colDesc.coltype === ENTupleColumnType.kIndex64 ||
-                        colDesc.coltype === ENTupleColumnType.kIndex32 ||
-                        colDesc.coltype === ENTupleColumnType.kSplitIndex64 ||
-                        colDesc.coltype === ENTupleColumnType.kSplitIndex32
-               ) // Index64/Index32
-                  rntuple._clusterData[field.fieldName][0] = values; // Offsets
-               else if (colDesc.coltype === ENTupleColumnType.kChar)
-                  rntuple._clusterData[field.fieldName][1] = values; // Payload
-               else
-                  throw new Error(`Unsupported column type for string field: ${colDesc.coltype}`);
-            } else
-               rntuple._clusterData[field.fieldName][0] = values;
-         }
+            if (!rntuple._clusterData[colDesc.index])
+               rntuple._clusterData[colDesc.index] = [];
 
-         // Ensure string fields have ending offset for proper reconstruction of the last entry
-         for (const fieldName of selectedFields) {
-            const field = builder.fieldDescriptors.find(f => f.fieldName === fieldName),
-                  colData = rntuple._clusterData[fieldName];
-            if (field.typeName === 'std::string') {
-               if (!Array.isArray(colData) || colData.length !== 2)
-                  throw new Error(`String field '${fieldName}' must have 2 columns`);
-               if (colData[0].length !== builder.clusterSummaries[clusterIndex].numEntries)
-                  throw new Error(`Malformed string field '${fieldName}': missing final offset`);
-            }
+            rntuple._clusterData[colDesc.index].push(values);
          }
 
          const numEntries = clusterSummary.numEntries;
          for (let i = 0; i < numEntries; ++i) {
             for (let b = 0; b < selector.numBranches(); ++b) {
                const fieldName = getSelectorFieldName(selector, b),
-                     tgtName = selector.nameOfBranch(b),
-                     values = rntuple._clusterData[fieldName];
+                     tgtName = selector.nameOfBranch(b);
 
-               if (!values)
-                  throw new Error(`Missing values for selected field: ${fieldName}`);
-               selector.tgtobj[tgtName] = readEntry(rntuple, fieldName, i);
+               selector.tgtobj[tgtName] = readEntry(rntuple, fieldName, clusterIndex, i);
             }
-            selector.Process();
+            selector.Process(selector.currentEntry++);
          }
 
-         selector.Terminate(true);
+         return readNextCluster(rntuple, selector);
       });
    });
 }
@@ -1112,6 +1094,7 @@ function rntupleProcess(rntuple, selector, args) {
    return readHeaderFooter(rntuple).then(() => {
       selector.Begin();
       selector.currentCluster = 0;
+      selector.currentEntry = 0;
       return readNextCluster(rntuple, selector, args);
    }).then(() => selector);
 }