diff --git a/demos/STM32/RT-STM32-LWIP-FATFS-USB/cfg/lwipopts.h b/demos/STM32/RT-STM32-LWIP-FATFS-USB/cfg/lwipopts.h
index e23a1f6f0..901683775 100644
--- a/demos/STM32/RT-STM32-LWIP-FATFS-USB/cfg/lwipopts.h
+++ b/demos/STM32/RT-STM32-LWIP-FATFS-USB/cfg/lwipopts.h
@@ -36,7 +36,19 @@
 #include "static_lwipopts.h"
 
 /* Optional, application-specific settings.*/
+#if !defined(TCPIP_MBOX_SIZE)
 #define TCPIP_MBOX_SIZE                 MEMP_NUM_PBUF
+#endif
+#if !defined(TCPIP_THREAD_STACKSIZE)
 #define TCPIP_THREAD_STACKSIZE          1024
+#endif
+
+/* Use ChibiOS specific priorities. */
+#if !defined(TCPIP_THREAD_PRIO)
+#define TCPIP_THREAD_PRIO               (LOWPRIO + 1)
+#endif
+#if !defined(LWIP_THREAD_PRIORITY)
+#define LWIP_THREAD_PRIORITY            (LOWPRIO)
+#endif
 
 #endif /* LWIP_HDR_LWIPOPTS_H__ */
diff --git a/demos/STM32/RT-STM32-LWIP-FATFS-USB/debug/RT-STM32-LWIP-FATFS-USB (Select ELF file)(OpenOCD, Flash and Run).launch b/demos/STM32/RT-STM32-LWIP-FATFS-USB/debug/RT-STM32-LWIP-FATFS-USB (Select ELF file)(OpenOCD, Flash and Run).launch
index 85e1e2c83..631cd8b2b 100644
--- a/demos/STM32/RT-STM32-LWIP-FATFS-USB/debug/RT-STM32-LWIP-FATFS-USB (Select ELF file)(OpenOCD, Flash and Run).launch	
+++ b/demos/STM32/RT-STM32-LWIP-FATFS-USB/debug/RT-STM32-LWIP-FATFS-USB (Select ELF file)(OpenOCD, Flash and Run).launch	
@@ -1,52 +1,52 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<launchConfiguration type="org.eclipse.cdt.debug.gdbjtag.launchConfigurationType">
-<stringAttribute key="bad_container_name" value="\RT-STM32-LWIP-FATFS-USB\debug"/>
-<intAttribute key="org.eclipse.cdt.debug.gdbjtag.core.delay" value="1"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.doHalt" value="true"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.doReset" value="true"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.imageFileName" value=""/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.imageOffset" value=""/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.initCommands" value="set remotetimeout 20&#13;&#10;monitor reset init&#13;&#10;monitor sleep 50&#13;&#10;"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.ipAddress" value="localhost"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.jtagDevice" value="Generic TCP/IP"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.loadImage" value="true"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.loadSymbols" value="true"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.pcRegister" value=""/>
-<intAttribute key="org.eclipse.cdt.debug.gdbjtag.core.portNumber" value="3333"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.runCommands" value=""/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setPcRegister" value="false"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setResume" value="true"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setStopAt" value="true"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.stopAt" value="main"/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.symbolsFileName" value=""/>
-<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.symbolsOffset" value=""/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useFileForImage" value="false"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useFileForSymbols" value="false"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useProjBinaryForImage" value="true"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useProjBinaryForSymbols" value="true"/>
-<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useRemoteTarget" value="true"/>
-<stringAttribute key="org.eclipse.cdt.debug.mi.core.DEBUG_NAME" value="arm-none-eabi-gdb"/>
-<stringAttribute key="org.eclipse.cdt.debug.mi.core.commandFactory" value="Standard"/>
-<stringAttribute key="org.eclipse.cdt.debug.mi.core.protocol" value="mi"/>
-<booleanAttribute key="org.eclipse.cdt.debug.mi.core.verboseMode" value="false"/>
-<stringAttribute key="org.eclipse.cdt.dsf.gdb.DEBUG_NAME" value="arm-none-eabi-gdb"/>
-<intAttribute key="org.eclipse.cdt.launch.ATTR_BUILD_BEFORE_LAUNCH_ATTR" value="2"/>
-<stringAttribute key="org.eclipse.cdt.launch.COREFILE_PATH" value=""/>
-<stringAttribute key="org.eclipse.cdt.launch.DEBUGGER_REGISTER_GROUPS" value=""/>
-<stringAttribute key="org.eclipse.cdt.launch.FORMAT" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&lt;contentList&gt;&lt;content id=&quot;xPSR-(format)&quot; val=&quot;4&quot;/&gt;&lt;/contentList&gt;"/>
-<stringAttribute key="org.eclipse.cdt.launch.GLOBAL_VARIABLES" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&#13;&#10;&lt;globalVariableList/&gt;&#13;&#10;"/>
-<stringAttribute key="org.eclipse.cdt.launch.MEMORY_BLOCKS" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&#13;&#10;&lt;memoryBlockExpressionList&gt;&#13;&#10;&lt;memoryBlockExpressionItem&gt;&#13;&#10;&lt;expression text=&quot;0x40021004&quot;/&gt;&#13;&#10;&lt;/memoryBlockExpressionItem&gt;&#13;&#10;&lt;/memoryBlockExpressionList&gt;&#13;&#10;"/>
-<stringAttribute key="org.eclipse.cdt.launch.PROGRAM_NAME" value="${selected_resource_loc}"/>
-<stringAttribute key="org.eclipse.cdt.launch.PROJECT_ATTR" value="RT-STM32-LWIP-FATFS-USB"/>
-<booleanAttribute key="org.eclipse.cdt.launch.PROJECT_BUILD_CONFIG_AUTO_ATTR" value="false"/>
-<stringAttribute key="org.eclipse.cdt.launch.PROJECT_BUILD_CONFIG_ID_ATTR" value=""/>
-<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_PATHS">
-<listEntry value="/RT-STM32-LWIP-FATFS-USB"/>
-</listAttribute>
-<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_TYPES">
-<listEntry value="4"/>
-</listAttribute>
-<listAttribute key="org.eclipse.debug.ui.favoriteGroups">
-<listEntry value="org.eclipse.debug.ui.launchGroup.debug"/>
-</listAttribute>
-</launchConfiguration>
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<launchConfiguration type="org.eclipse.cdt.debug.gdbjtag.launchConfigurationType">
+<stringAttribute key="bad_container_name" value="\RT-STM32-LWIP-FATFS-USB\debug"/>
+<intAttribute key="org.eclipse.cdt.debug.gdbjtag.core.delay" value="1"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.doHalt" value="true"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.doReset" value="true"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.imageFileName" value=""/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.imageOffset" value=""/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.initCommands" value="set remotetimeout 20&#13;&#10;monitor reset init&#13;&#10;monitor sleep 50&#13;&#10;"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.ipAddress" value="localhost"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.jtagDevice" value="Generic TCP/IP"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.loadImage" value="true"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.loadSymbols" value="true"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.pcRegister" value=""/>
+<intAttribute key="org.eclipse.cdt.debug.gdbjtag.core.portNumber" value="3333"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.runCommands" value=""/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setPcRegister" value="false"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setResume" value="true"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.setStopAt" value="true"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.stopAt" value="main"/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.symbolsFileName" value=""/>
+<stringAttribute key="org.eclipse.cdt.debug.gdbjtag.core.symbolsOffset" value=""/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useFileForImage" value="false"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useFileForSymbols" value="false"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useProjBinaryForImage" value="true"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useProjBinaryForSymbols" value="true"/>
+<booleanAttribute key="org.eclipse.cdt.debug.gdbjtag.core.useRemoteTarget" value="true"/>
+<stringAttribute key="org.eclipse.cdt.debug.mi.core.DEBUG_NAME" value="arm-none-eabi-gdb"/>
+<stringAttribute key="org.eclipse.cdt.debug.mi.core.commandFactory" value="Standard"/>
+<stringAttribute key="org.eclipse.cdt.debug.mi.core.protocol" value="mi"/>
+<booleanAttribute key="org.eclipse.cdt.debug.mi.core.verboseMode" value="false"/>
+<stringAttribute key="org.eclipse.cdt.dsf.gdb.DEBUG_NAME" value="arm-none-eabi-gdb"/>
+<intAttribute key="org.eclipse.cdt.launch.ATTR_BUILD_BEFORE_LAUNCH_ATTR" value="2"/>
+<stringAttribute key="org.eclipse.cdt.launch.COREFILE_PATH" value=""/>
+<stringAttribute key="org.eclipse.cdt.launch.DEBUGGER_REGISTER_GROUPS" value=""/>
+<stringAttribute key="org.eclipse.cdt.launch.FORMAT" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&lt;contentList&gt;&lt;content id=&quot;xPSR-(format)&quot; val=&quot;4&quot;/&gt;&lt;/contentList&gt;"/>
+<stringAttribute key="org.eclipse.cdt.launch.GLOBAL_VARIABLES" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&#10;&lt;globalVariableList/&gt;&#10;"/>
+<stringAttribute key="org.eclipse.cdt.launch.MEMORY_BLOCKS" value="&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; standalone=&quot;no&quot;?&gt;&#10;&lt;memoryBlockExpressionList&gt;&#10;&lt;memoryBlockExpressionItem&gt;&#10;&lt;expression text=&quot;0x40021004&quot;/&gt;&#10;&lt;/memoryBlockExpressionItem&gt;&#10;&lt;/memoryBlockExpressionList&gt;&#10;"/>
+<stringAttribute key="org.eclipse.cdt.launch.PROGRAM_NAME" value="${selected_resource_loc}"/>
+<stringAttribute key="org.eclipse.cdt.launch.PROJECT_ATTR" value="RT-STM32-LWIP-FATFS-USB"/>
+<booleanAttribute key="org.eclipse.cdt.launch.PROJECT_BUILD_CONFIG_AUTO_ATTR" value="false"/>
+<stringAttribute key="org.eclipse.cdt.launch.PROJECT_BUILD_CONFIG_ID_ATTR" value=""/>
+<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_PATHS">
+<listEntry value="/RT-STM32-LWIP-FATFS-USB"/>
+</listAttribute>
+<listAttribute key="org.eclipse.debug.core.MAPPED_RESOURCE_TYPES">
+<listEntry value="4"/>
+</listAttribute>
+<listAttribute key="org.eclipse.debug.ui.favoriteGroups">
+<listEntry value="org.eclipse.debug.ui.launchGroup.debug"/>
+</listAttribute>
+</launchConfiguration>
diff --git a/os/various/lwip_bindings/static_lwipopts.h b/os/various/lwip_bindings/static_lwipopts.h
index 3f3e9b3da..a59d4b41a 100644
--- a/os/various/lwip_bindings/static_lwipopts.h
+++ b/os/various/lwip_bindings/static_lwipopts.h
@@ -31,7 +31,7 @@
 
 #define LWIP_TCPIP_CORE_LOCKING         1
 #define LWIP_TCPIP_CORE_LOCKING_INPUT   0
-#define LWIP_COMPAT_MUTEX_ALLOWED
+#define LWIP_COMPAT_MUTEX_ALLOWED       1
 
 #define SYS_LIGHTWEIGHT_PROT            0