diff --git a/emsdk/Makefile b/emsdk/Makefile
index 56f6800c5..fb75fd548 100644
--- a/emsdk/Makefile
+++ b/emsdk/Makefile
@@ -1,9 +1,7 @@
 all: emsdk/.complete
 
 # We hack the CPU_CORES, because if you use all of the cores on Circle-CI, you
-# run out of memory
-
-
+# run out of memory.
 
 emsdk/.complete:
 	if [ -d emsdk ]; then rm -rf emsdk; fi
diff --git a/emsdk/patches/lz4_c.patch b/emsdk/patches/lz4_c.patch
index ab5a76fb7..76ec06146 100644
--- a/emsdk/patches/lz4_c.patch
+++ b/emsdk/patches/lz4_c.patch
@@ -1,8 +1,8 @@
-diff --git a/src/library_lz4.js b/src/library_lz4.js
-index 4c3f583b7..9540a64fb 100644
+diff --git a/emsdk/emscripten/tag-1.38.10/src/library_lz4.js b/emsdk/emscripten/tag-1.38.10/src/library_lz4.js
+index 4c3f583b7..5291002a4 100644
 --- a/src/library_lz4.js
 +++ b/src/library_lz4.js
-@@ -5,26 +5,15 @@ mergeInto(LibraryManager.library, {
+@@ -5,26 +5,14 @@ mergeInto(LibraryManager.library, {
      DIR_MODE: {{{ cDefine('S_IFDIR') }}} | 511 /* 0777 */,
      FILE_MODE: {{{ cDefine('S_IFREG') }}} | 511 /* 0777 */,
      CHUNK_SIZE: -1,
@@ -28,11 +28,23 @@ index 4c3f583b7..9540a64fb 100644
 -                                                                      compressedData.cachedOffset + (i+1)*LZ4.CHUNK_SIZE);
 -        assert(compressedData.cachedChunks[i].length === LZ4.CHUNK_SIZE);
 -      }
-+      compressedData.buf = null;
        pack['metadata'].files.forEach(function(file) {
          var dir = PATH.dirname(file.filename);
          var name = PATH.basename(file.filename);
-@@ -112,8 +101,17 @@ mergeInto(LibraryManager.library, {
+@@ -36,6 +24,12 @@ mergeInto(LibraryManager.library, {
+           end: file.end,
+         });
+       });
++      compressedData.buf = Module['_malloc'](LZ4.CHUNK_SIZE);
++      for (var i = 0; i < compressedData.cachedIndexes.length; i++) {
++        compressedData.cachedIndexes[i] = -1;
++        compressedData.cachedChunks[i] = Module['_malloc'](LZ4.CHUNK_SIZE);
++        assert(compressedData.cachedChunks[i] !== null)
++      }
+     },
+     createNode: function (parent, name, mode, dev, contents, mtime) {
+       var node = FS.createNode(parent, name, mode);
+@@ -112,8 +106,17 @@ mergeInto(LibraryManager.library, {
          //console.log('LZ4 read ' + [offset, length, position]);
          length = Math.min(length, stream.node.size - position);
          if (length <= 0) return 0;
@@ -50,7 +62,16 @@ index 4c3f583b7..9540a64fb 100644
          var written = 0;
          while (written < length) {
            var start = contents.start + position + written; // start index in uncompressed data
-@@ -138,18 +136,23 @@ mergeInto(LibraryManager.library, {
+@@ -122,6 +125,8 @@ mergeInto(LibraryManager.library, {
+           var chunkIndex = Math.floor(start / LZ4.CHUNK_SIZE);
+           var compressedStart = compressedData.offsets[chunkIndex];
+           var compressedSize = compressedData.sizes[chunkIndex];
++          var startInChunk = start % LZ4.CHUNK_SIZE;
++          var endInChunk = Math.min(startInChunk + desired, LZ4.CHUNK_SIZE);
+           var currChunk;
+           if (compressedData.successes[chunkIndex]) {
+             var found = compressedData.cachedIndexes.indexOf(chunkIndex);
+@@ -138,18 +143,19 @@ mergeInto(LibraryManager.library, {
                  Module['decompressedChunks'] = (Module['decompressedChunks'] || 0) + 1;
                }
                var compressed = compressedData.data.subarray(compressedStart, compressedStart + compressedSize);
@@ -63,24 +84,22 @@ index 4c3f583b7..9540a64fb 100644
 +              var originalSize = Module['_LZ4_decompress_safe'](compressedData.buf, currChunk, compressedSize, LZ4.CHUNK_SIZE);
 +              // console.log('decompress time: ' + (Date.now() - t));
                if (chunkIndex < compressedData.successes.length-1) assert(originalSize === LZ4.CHUNK_SIZE); // all but the last chunk must be full-size
++              buffer.set(Module.HEAPU8.subarray(currChunk + startInChunk, currChunk + endInChunk), offset + written);
              }
 -          } else {
 +          }
 +          else {
              // uncompressed
 -            currChunk = compressedData.data.subarray(compressedStart, compressedStart + LZ4.CHUNK_SIZE);
-+            var compressed = compressedData.data.subarray(compressedStart, compressedStart + LZ4.CHUNK_SIZE);
-+            Module.HEAPU8.set(compressed, compressedData.buf);
-+            currChunk = compressedData.buf;
++            buffer.set(compressedData.data.subarray(compressedStart + startInChunk, compressedStart + endInChunk), offset + written);
            }
-           var startInChunk = start % LZ4.CHUNK_SIZE;
-           var endInChunk = Math.min(startInChunk + desired, LZ4.CHUNK_SIZE);
+-          var startInChunk = start % LZ4.CHUNK_SIZE;
+-          var endInChunk = Math.min(startInChunk + desired, LZ4.CHUNK_SIZE);
 -          buffer.set(currChunk.subarray(startInChunk, endInChunk), offset + written);
-+          buffer.set(Module.HEAPU8.subarray(currChunk + startInChunk, currChunk + endInChunk), offset + written);
            var currWritten = endInChunk - startInChunk;
            written += currWritten;
          }
-@@ -181,4 +184,3 @@ if (LibraryManager.library['$FS__deps']) {
+@@ -181,4 +187,3 @@ if (LibraryManager.library['$FS__deps']) {
    warn('FS does not seem to be in use (no preloaded files etc.), LZ4 will not do anything');
  }
  #endif