diff --git a/emulator/.gitignore b/emulator/.gitignore
index 85a56464..f5ce32e2 100644
--- a/emulator/.gitignore
+++ b/emulator/.gitignore
@@ -8,3 +8,4 @@ generated-src
 generated-src-debug
 kernel
 kernel.hex
+verilator/
diff --git a/emulator/Makefrag-verilator b/emulator/Makefrag-verilator
index b0489c59..59be0aa8 100644
--- a/emulator/Makefrag-verilator
+++ b/emulator/Makefrag-verilator
@@ -28,7 +28,34 @@ $(generated_dir_debug)/%.$(CONFIG).fir $(generated_dir_debug)/%.$(CONFIG).prm $(
 	mkdir -p $(dir $@)
 	$(FIRRTL) $(patsubst %,-i %,$(filter %.fir,$^)) -o $@ -X verilog
 
-VERILATOR := verilator --cc --exe
+# Build and install our own Verilator, to work around versionining issues.
+VERILATOR_VERSION=3.884
+VERILATOR_SRCDIR=verilator/src/verilator-$(VERILATOR_VERSION)
+INSTALLED_VERILATOR=$(abspath verilator/install/bin/verilator)
+$(INSTALLED_VERILATOR): $(VERILATOR_SRCDIR)/bin/verilator
+	$(MAKE) -C $(VERILATOR_SRCDIR) install
+	touch $@
+
+$(VERILATOR_SRCDIR)/bin/verilator: $(VERILATOR_SRCDIR)/Makefile
+	$(MAKE) -C $(VERILATOR_SRCDIR)
+	touch $@
+
+$(VERILATOR_SRCDIR)/Makefile: $(VERILATOR_SRCDIR)/configure
+	mkdir -p $(dir $@)
+	cd $(dir $@) && ./configure --prefix=$(abspath verilator/install)
+
+$(VERILATOR_SRCDIR)/configure: verilator/verilator-$(VERILATOR_VERSION).tar.gz
+	rm -rf $(dir $@)
+	mkdir -p $(dir $@)
+	cat $^ | tar -xz --strip-components=1 -C $(dir $@)
+	touch $@
+
+verilator/verilator-$(VERILATOR_VERSION).tar.gz:
+	mkdir -p $(dir $@)
+	wget http://www.veripool.org/ftp/verilator-$(VERILATOR_VERSION).tgz -O $@
+
+# Run Verilator to produce a fast binary to emulate this circuit.
+VERILATOR := $(INSTALLED_VERILATOR) --cc --exe
 VERILATOR_FLAGS := --top-module $(MODEL) +define+PRINTF_COND=$(MODEL).reset --assert \
 	-Wno-UNSIGNED -Wno-COMBDLY -Wno-MULTIDRIVEN -Wno-WIDTH -Wno-STMTDLY -Wno-SELRANGE -Wno-IMPLICIT
 cppfiles = $(addprefix $(base_dir)/csrc/, $(addsuffix .cc, $(CXXSRCS)))
@@ -42,14 +69,14 @@ $(addsuffix .o,$(CXXSRCS)): %.o: $(base_dir)/csrc/%.cc $(base_dir)/csrc/*.h $(co
 $(addsuffix .debug.o,$(CXXSRCS)): %.debug.o: $(base_dir)/csrc/%.cc $(base_dir)/csrc/*.h $(consts_header_debug)
 	$(CXX) $(CXXFLAGS) -DVERILATOR -I$(generated_dir_debug) -c -o $@ $<
 
-$(emu): $(verilog) $(cppfiles) libdramsim.a $(consts_header)
+$(emu): $(verilog) $(cppfiles) libdramsim.a $(consts_header) $(INSTALLED_VERILATOR)
 	mkdir -p $(generated_dir)/$(MODEL).$(CONFIG)
 	$(VERILATOR) $(VERILATOR_FLAGS) -Mdir $(generated_dir)/$(MODEL).$(CONFIG) \
 	-o $(abspath $(sim_dir))/$@ $< $(cppfiles) -LDFLAGS "$(LDFLAGS)" \
 	-CFLAGS "$(CXXFLAGS) -DVERILATOR -I$(generated_dir) -include $(model_header) -include $(consts_header) -include $(scr_header)"
 	$(MAKE) -C $(generated_dir)/$(MODEL).$(CONFIG) -f V$(MODEL).mk
 
-$(emu_debug): $(verilog_debug) $(cppfiles) libdramsim.a $(consts_header_debug) $(generated_dir)/$(MODEL).$(CONFIG).d
+$(emu_debug): $(verilog_debug) $(cppfiles) libdramsim.a $(consts_header_debug) $(generated_dir)/$(MODEL).$(CONFIG).d $(INSTALLED_VERILATOR)
 	mkdir -p $(generated_dir_debug)/$(MODEL).$(CONFIG)
 	$(VERILATOR) $(VERILATOR_FLAGS) -Mdir $(generated_dir_debug)/$(MODEL).$(CONFIG)  --trace \
 	-o $(abspath $(sim_dir))/$@ $< $(cppfiles) -LDFLAGS "$(LDFLAGS)" \