diff --git a/CHANGELOG.md b/CHANGELOG.md
index 594c791..bf6f1cf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,21 @@
 # Changelog
 
+## v1.6.4
+
+Critical bugfix for the embedded firmware:
+
+- Fix SPI flash timing, see #315
+
+Minor improvement for the GUI:
+
+- Option to add titles to graphs
+- Show trace names even when only enabled on secondary Y axis
+- Add x axis variable to the available variables for formulas in "from math" traces
+
+
+
 ## v1.6.3
+
 Bugfixes and quality of life improvements
 
 - Windows and macOS: add icon to GUI application
diff --git a/Software/PC_Application/LibreVNA-GUI/LibreVNA-GUI.pro b/Software/PC_Application/LibreVNA-GUI/LibreVNA-GUI.pro
index c070682..d067010 100644
--- a/Software/PC_Application/LibreVNA-GUI/LibreVNA-GUI.pro
+++ b/Software/PC_Application/LibreVNA-GUI/LibreVNA-GUI.pro
@@ -416,5 +416,5 @@ QMAKE_CXXFLAGS += -Wno-deprecated -Wno-deprecated-declarations -Wno-deprecated-c
 CONFIG += c++17
 REVISION = $$system(git rev-parse HEAD)
 DEFINES += GITHASH=\\"\"$$REVISION\\"\"
-DEFINES += FW_MAJOR=1 FW_MINOR=6 FW_PATCH=3 FW_SUFFIX=""
+DEFINES += FW_MAJOR=1 FW_MINOR=6 FW_PATCH=4 FW_SUFFIX=""
 DEFINES -= _UNICODE UNICODE
diff --git a/Software/PC_Application/LibreVNA-Test/LibreVNA-Test.pro b/Software/PC_Application/LibreVNA-Test/LibreVNA-Test.pro
index 9c25927..bf0872e 100644
--- a/Software/PC_Application/LibreVNA-Test/LibreVNA-Test.pro
+++ b/Software/PC_Application/LibreVNA-Test/LibreVNA-Test.pro
@@ -443,6 +443,6 @@ unix:LIBS += -L/usr/lib/
 
 REVISION = $$system(git rev-parse HEAD)
 DEFINES += GITHASH=\\"\"$$REVISION\\"\"
-DEFINES += FW_MAJOR=1 FW_MINOR=6 FW_PATCH=2 FW_SUFFIX=""#\\"\"-alpha.2\\"\"
+DEFINES += FW_MAJOR=1 FW_MINOR=6 FW_PATCH=4 FW_SUFFIX=""#\\"\"-alpha.2\\"\"
 DEFINES -= _UNICODE UNICODE
 win32:DEFINES += QMICROZ_LIBRARY
diff --git a/Software/VNA_embedded/.cproject b/Software/VNA_embedded/.cproject
index b1393ba..67f1bd9 100644
--- a/Software/VNA_embedded/.cproject
+++ b/Software/VNA_embedded/.cproject
@@ -44,7 +44,7 @@
 									<listOptionValue builtIn="false" value="_SNK"/>
 									<listOptionValue builtIn="false" value="FW_MAJOR=1"/>
 									<listOptionValue builtIn="false" value="FW_MINOR=6"/>
-									<listOptionValue builtIn="false" value="FW_PATCH=3"/>
+									<listOptionValue builtIn="false" value="FW_PATCH=4"/>
 									<listOptionValue builtIn="false" value="HW_REVISION='B'"/>
 									<listOptionValue builtIn="false" value="USE_FULL_LL_DRIVER"/>
 									<listOptionValue builtIn="false" value="USE_HAL_DRIVER"/>
@@ -91,7 +91,7 @@
 									<listOptionValue builtIn="false" value="DEBUG"/>
 									<listOptionValue builtIn="false" value="FW_MAJOR=1"/>
 									<listOptionValue builtIn="false" value="FW_MINOR=6"/>
-									<listOptionValue builtIn="false" value="FW_PATCH=3"/>
+									<listOptionValue builtIn="false" value="FW_PATCH=4"/>
 									<listOptionValue builtIn="false" value="HW_REVISION='B'"/>
 									<listOptionValue builtIn="false" value="USE_FULL_LL_DRIVER"/>
 									<listOptionValue builtIn="false" value="USE_HAL_DRIVER"/>
diff --git a/Software/VNA_embedded/Makefile b/Software/VNA_embedded/Makefile
index 2ef881b..ae3b667 100644
--- a/Software/VNA_embedded/Makefile
+++ b/Software/VNA_embedded/Makefile
@@ -101,7 +101,7 @@ MCU = $(CPU) -mthumb $(FLOAT-ABI) $(FPU)
 C_DEFS =  \
 -DFW_MAJOR=1 \
 -DFW_MINOR=6 \
--DFW_PATCH=3 \
+-DFW_PATCH=4 \
 -DDEBUG \
 -DUSE_FULL_LL_DRIVER \
 -DHW_REVISION="'B'" \