diff --git a/HISTORY.md b/HISTORY.md
index ca117b273..80cac265b 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -1,6 +1,8 @@
 # Rocksdb Change Log
 
 ## Unreleased (will be released with 3.6)
+### Disk format changes
+* If you're using RocksDB on ARM platforms and you're using default bloom filter, there is a disk format change you need to be aware of. There are three steps you need to do when you convert to new release: 1. turn off filter policy, 2. compact the whole database, 3. turn on filter policy 
 
 ### Behavior changes
 * We have refactored our system of stalling writes.  Any stall-related statistics' meanings are changed. Instead of per-write stall counts, we now count stalls per-epoch, where epochs are periods between flushes and compactions. You'll find more information in our Tuning Perf Guide once we release RocksDB 3.6.
diff --git a/tools/auto_sanity_test.sh b/tools/auto_sanity_test.sh
index 2d63c0a85..138c855c0 100755
--- a/tools/auto_sanity_test.sh
+++ b/tools/auto_sanity_test.sh
@@ -37,6 +37,11 @@ echo "Running db sanity check with commits $commit_new and $commit_old."
 
 echo "============================================================="
 echo "Making build $commit_new"
+git checkout $commit_new
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Can't checkout $commit_new"
+  exit 1
+fi
 makestuff
 mv db_sanity_test new_db_sanity_test
 echo "Creating db based on the new commit --- $commit_new"
@@ -44,6 +49,11 @@ echo "Creating db based on the new commit --- $commit_new"
 
 echo "============================================================="
 echo "Making build $commit_old"
+git checkout $commit_old
+if [ $? -ne 0 ]; then
+  echo "[ERROR] Can't checkout $commit_old"
+  exit 1
+fi
 makestuff
 mv db_sanity_test old_db_sanity_test
 echo "Creating db based on the old commit --- $commit_old"
diff --git a/tools/db_sanity_test.cc b/tools/db_sanity_test.cc
index 7cf7c1cca..237ef07d0 100644
--- a/tools/db_sanity_test.cc
+++ b/tools/db_sanity_test.cc
@@ -8,15 +8,15 @@
 #include <vector>
 #include <memory>
 
-#include "include/rocksdb/db.h"
-#include "include/rocksdb/options.h"
-#include "include/rocksdb/env.h"
-#include "include/rocksdb/slice.h"
-#include "include/rocksdb/status.h"
-#include "include/rocksdb/comparator.h"
-#include "include/rocksdb/table.h"
-#include "include/rocksdb/slice_transform.h"
-#include "include/rocksdb/filter_policy.h"
+#include "rocksdb/db.h"
+#include "rocksdb/options.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/status.h"
+#include "rocksdb/comparator.h"
+#include "rocksdb/table.h"
+#include "rocksdb/slice_transform.h"
+#include "rocksdb/filter_policy.h"
 
 namespace rocksdb {
 
@@ -50,7 +50,7 @@ class SanityTest {
         return s;
       }
     }
-    return Status::OK();
+    return db->Flush(FlushOptions());
   }
   Status Verify() {
     DB* db;
@@ -149,10 +149,10 @@ class SanityTestPlainTableFactory : public SanityTest {
 
 class SanityTestBloomFilter : public SanityTest {
  public:
-  explicit SanityTestBloomFilter(const std::string& path)
-      : SanityTest(path) {
-    table_options_.filter_policy.reset(NewBloomFilterPolicy(10));
-    options_.table_factory.reset(NewBlockBasedTableFactory(table_options_));
+  explicit SanityTestBloomFilter(const std::string& path) : SanityTest(path) {
+    BlockBasedTableOptions table_options;
+    table_options.filter_policy.reset(NewBloomFilterPolicy(10));
+    options_.table_factory.reset(NewBlockBasedTableFactory(table_options));
   }
   ~SanityTestBloomFilter() {}
   virtual Options GetOptions() const { return options_; }
@@ -160,7 +160,6 @@ class SanityTestBloomFilter : public SanityTest {
 
  private:
   Options options_;
-  BlockBasedTableOptions table_options_;
 };
 
 namespace {
diff --git a/util/hash.cc b/util/hash.cc
index e38c186c3..37eaa4057 100644
--- a/util/hash.cc
+++ b/util/hash.cc
@@ -31,14 +31,26 @@ uint32_t Hash(const char* data, size_t n, uint32_t seed) {
 
   // Pick up remaining bytes
   switch (limit - data) {
+    // Note: It would be better if this was cast to unsigned char, but that
+    // would be a disk format change since we previously didn't have any cast
+    // at all (so gcc used signed char).
+    // To understand the difference between shifting unsigned and signed chars,
+    // let's use 250 as an example. unsigned char will be 250, while signed char
+    // will be -6. Bit-wise, they are equivalent: 11111010. However, when
+    // converting negative number (signed char) to int, it will be converted
+    // into negative int (of equivalent value, which is -6), while converting
+    // positive number (unsigned char) will be converted to 250. Bitwise,
+    // this looks like this:
+    // signed char 11111010 -> int 11111111111111111111111111111010
+    // unsigned char 11111010 -> int 00000000000000000000000011111010
     case 3:
-      h += data[2] << 16;
-      // fall through
+      h += static_cast<uint32_t>(static_cast<signed char>(data[2]) << 16);
+    // fall through
     case 2:
-      h += data[1] << 8;
-      // fall through
+      h += static_cast<uint32_t>(static_cast<signed char>(data[1]) << 8);
+    // fall through
     case 1:
-      h += data[0];
+      h += static_cast<uint32_t>(static_cast<signed char>(data[0]));
       h *= m;
       h ^= (h >> r);
       break;