diff --git a/CHANGES b/CHANGES
index 0f8a19e..7e22fdc 100644
--- a/CHANGES
+++ b/CHANGES
@@ -15,3 +15,5 @@ v0.4
 
 - Tools rolled into a single executable to save space.
 
+- Fixed some bugs when walking bitsets (possibly effecting cache_dump
+  and cache_check).
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
index 06a7697..d05c7a1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    aruba (0.6.0)
+    aruba (0.6.1)
       childprocess (>= 0.3.6)
       cucumber (>= 1.1.1)
       rspec-expectations (>= 2.7.0)
@@ -21,11 +21,11 @@ GEM
       multi_json (~> 1.3)
     multi_json (1.10.1)
     multi_test (0.1.1)
-    rspec-expectations (3.0.3)
+    rspec-expectations (3.0.4)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.0.0)
-    rspec-support (3.0.3)
-    thinp_xml (0.0.18)
+    rspec-support (3.0.4)
+    thinp_xml (0.0.19)
       ejt_command_line (>= 0.0.2)
 
 PLATFORMS
diff --git a/Makefile.in b/Makefile.in
index 339fbc5..ff2a2a3 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -16,11 +16,13 @@
 # with thin-provisioning-tools.  If not, see
 # <http://www.gnu.org/licenses/>.
 
-.PHONY: all
-
 V=@
 
-all: bin/pdata_tools
+PROGRAMS=\
+	bin/pdata_tools
+
+.PHONY: all
+all: $(PROGRAMS)
 
 SOURCE=\
 	base/application.cc \
diff --git a/VERSION b/VERSION
index d15723f..1d0ba9e 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.2
+0.4.0
diff --git a/base/xml_utils.h b/base/xml_utils.h
index 581e814..f867f56 100644
--- a/base/xml_utils.h
+++ b/base/xml_utils.h
@@ -7,6 +7,7 @@
 #include <expat.h>
 #include <iosfwd>
 #include <map>
+#include <stdexcept>
 
 using namespace std;
 
diff --git a/caching/cache_metadata_size.cc b/caching/cache_metadata_size.cc
index 3fb1bf1..dd806c8 100644
--- a/caching/cache_metadata_size.cc
+++ b/caching/cache_metadata_size.cc
@@ -17,6 +17,15 @@ namespace {
 	struct flags {
 		flags()
 			: max_hint_width(4) {
+
+			// Dance around some spurious compiler warnings
+			device_size = 0;
+			block_size = 0;
+			nr_blocks = 0;
+
+			device_size.reset();
+			block_size.reset();
+			nr_blocks.reset();
 		}
 
 		boost::optional<uint64_t> device_size;
diff --git a/era/era_invalidate.cc b/era/era_invalidate.cc
index 45ae784..c81b5af 100644
--- a/era/era_invalidate.cc
+++ b/era/era_invalidate.cc
@@ -88,9 +88,14 @@ namespace {
 		walk_writeset_tree(md.tm_, *md.writeset_tree_, v, dv);
 	}
 
-	void mark_blocks_since(metadata const &md, uint32_t threshold, set<uint32_t> &result) {
-		walk_array(*md.era_array_, md.sb_.nr_blocks, threshold, result);
-		walk_writesets(md, threshold, result);
+	void mark_blocks_since(metadata const &md, optional<uint32_t> const &threshold, set<uint32_t> &result) {
+		if (!threshold)
+			// Can't get here, just putting in to pacify the compiler
+			throw std::runtime_error("threshold not set");
+		else {
+			walk_array(*md.era_array_, md.sb_.nr_blocks, *threshold, result);
+			walk_writesets(md, *threshold, result);
+		}
 	}
 
 	//--------------------------------
@@ -155,11 +160,11 @@ namespace {
 					throw runtime_error("no metadata snapshot taken.");
 
 				metadata::ptr md(new metadata(bm, *sb.metadata_snap));
-				mark_blocks_since(*md, *fs.era_threshold_, blocks);
+				mark_blocks_since(*md, fs.era_threshold_, blocks);
 
 			} else {
 				metadata::ptr md(new metadata(bm, metadata::OPEN));
-				mark_blocks_since(*md, *fs.era_threshold_, blocks);
+				mark_blocks_since(*md, fs.era_threshold_, blocks);
 			}
 
 			if (want_stdout(output))
diff --git a/features/cache_dump.feature b/features/cache_dump.feature
index 4011c20..3415c6a 100644
--- a/features/cache_dump.feature
+++ b/features/cache_dump.feature
@@ -44,7 +44,7 @@ Feature: cache_dump
 
   Scenario: dump/restore is a noop
     Given valid cache metadata
-    When I cache_dump
-    And I cache_restore
-    And I cache_dump
+    When I cache dump
+    And I cache restore
+    And I cache dump
     Then cache dumps 1 and 2 should be identical