diff --git a/HxCFloppyEmulator_cmdline/build/Makefile b/HxCFloppyEmulator_cmdline/build/Makefile
index 977c92f0..9d0134ee 100644
--- a/HxCFloppyEmulator_cmdline/build/Makefile
+++ b/HxCFloppyEmulator_cmdline/build/Makefile
@@ -9,6 +9,8 @@ DEBUG ?= 0
 DEBUG_ASAN ?= 0
 DEBUG_INFOS ?= 0
 
+PTHREAD ?= 0
+
 ifeq ($(DEBUG), 1)
 	CFLAGS =-O0 $(INCLUDES) -Wall -DDEBUG
 	LDFLAGS =
@@ -76,6 +78,10 @@ endif
 ifeq ($(TARGET), Emscripten)
 	CFLAGS +=
 	LDFLAGS += -static-libgcc
+	ifeq ($(PTHREAD), 1)
+		CFLAGS += -pthread
+		LDFLAGS += -pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB
+	endif
 	CC = emcc
 	EXEC = hxcfe.wasm
 	LIBHXCFE = libhxcfe.a
diff --git a/HxCFloppyEmulator_software/build/Makefile b/HxCFloppyEmulator_software/build/Makefile
index f4c6f43a..ab6123e9 100644
--- a/HxCFloppyEmulator_software/build/Makefile
+++ b/HxCFloppyEmulator_software/build/Makefile
@@ -13,6 +13,8 @@ DEBUG ?= 0
 DEBUG_ASAN ?= 0
 DEBUG_INFOS ?= 0
 
+PTHREAD ?= 0
+
 EXEC = hxcfloppyemulator
 
 ifeq ($(DEBUG), 1)
@@ -100,13 +102,17 @@ else
 endif
 
 ifeq ($(TARGET), Emscripten)
-	CFLAGS += -I/usr/local/include -pthread
-	LDFLAGS += -lc -lm -ldl	
+	CFLAGS += -I/usr/local/include
+	LDFLAGS += -lc -lm -ldl
+	ifeq ($(PTHREAD), 1)
+		CFLAGS += -pthread
+		LDFLAGS += -pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB
+	endif
 	CC = emcc
 	CPP = em++
 	BUILD_CC = cc
 	LIBHXCFE = libhxcfe.a
-	LIBUSBHXCFE = libusbhxcfe.a	
+	LIBUSBHXCFE = libusbhxcfe.a
 	LDFLAGS += -lpthread -s WASM=1 -sALLOW_MEMORY_GROWTH -sASYNCIFY -sOFFSCREENCANVAS_SUPPORT=1 --bind --shell-file $(realpath $(BASEDIR))/gui/wasm/shell.html
 	EXEC = hxcfloppyemulator.html
 endif
@@ -140,7 +146,11 @@ else ifeq ($(TARGET), mingw64)
 		cd ../sources/thirdpartylibs/fltk/fltk-1.x.x/ && export LDFLAGS='-static-libstdc++ -static-libgcc' && ./configure --host=x86_64-w64-mingw32 --prefix=/usr/share/mingw-w64
 		$(MAKE) -C ../sources/thirdpartylibs/fltk/fltk-1.x.x/ DIRS=src CC=x86_64-w64-mingw32-gcc CPP=x86_64-w64-mingw32-g++
 else ifeq ($(TARGET), Emscripten)
-		cd ../sources/thirdpartylibs/fltk/fltk-1.x.x/ && export LDFLAGS='-s WASM=1 -sALLOW_MEMORY_GROWTH -sASYNCIFY -sOFFSCREENCANVAS_SUPPORT=1 --bind --shell-file $(realpath $(BASEDIR))/gui/wasm/shell.html' && emcmake cmake -DCMAKE_BUILD_TYPE=Release -DFLTK_BUILD_TEST:BOOL=OFF -DFLTK_USE_PTHREADS:BOOL=OFF -DFLTK_BUILD_FLUID:BOOL=OFF -DFLTK_BUILD_FLTK_OPTIONS:BOOL=OFF -DFLTK_BUILD_GL:BOOL=OFF && emmake make DIRS=src 
+ifeq ($(PTHREAD), 1)
+	cd ../sources/thirdpartylibs/fltk/fltk-1.x.x/ && export LDFLAGS='-pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB -s WASM=1 -sALLOW_MEMORY_GROWTH -sASYNCIFY -sOFFSCREENCANVAS_SUPPORT=1 --bind --shell-file $(realpath $(BASEDIR))/gui/wasm/shell.html' && emcmake cmake -DCMAKE_BUILD_TYPE=Release  -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON -DFLTK_BUILD_TEST:BOOL=OFF -DFLTK_CFLAGS="-pthread" -DCMAKE_CXX_FLAGS="-pthread" -DCMAKE_C_FLAGS="-pthread" -DFLTK_USE_PTHREADS:BOOL=ON -DFLTK_BUILD_FLUID:BOOL=OFF -DFLTK_BUILD_FLTK_OPTIONS:BOOL=OFF -DFLTK_BUILD_GL:BOOL=OFF && emmake make DIRS=src
+else
+	cd ../sources/thirdpartylibs/fltk/fltk-1.x.x/ && export LDFLAGS='-s WASM=1 -sALLOW_MEMORY_GROWTH -sASYNCIFY -sOFFSCREENCANVAS_SUPPORT=1 --bind --shell-file $(realpath $(BASEDIR))/gui/wasm/shell.html' && emcmake cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON -DFLTK_BUILD_TEST:BOOL=OFF -DFLTK_USE_PTHREADS:BOOL=OFF -DFLTK_BUILD_FLUID:BOOL=OFF -DFLTK_BUILD_FLTK_OPTIONS:BOOL=OFF -DFLTK_BUILD_GL:BOOL=OFF && emmake make DIRS=src
+endif
 else ifeq ($(TARGET), Darwin)
 ifneq (,$(findstring arm64,$(MACOSX_ARCH)))
 		cd ../sources/thirdpartylibs/fltk && \
@@ -351,7 +361,7 @@ clean:
 	rm -rf *.a
 	rm -rf *.wasm
 	rm -rf *.js
-	rm -rf *.html	
+	rm -rf *.html
 	rm -rf *.o
 	rm -rf *.so
 	rm -rf *.dll
diff --git a/libhxcadaptor/build/Makefile b/libhxcadaptor/build/Makefile
index b998e1b9..34a3c499 100644
--- a/libhxcadaptor/build/Makefile
+++ b/libhxcadaptor/build/Makefile
@@ -11,6 +11,8 @@ DEBUG ?= 0
 DEBUG_ASAN ?= 0
 DEBUG_INFOS ?= 0
 
+PTHREAD ?= 0
+
 ifeq ($(DEBUG), 1)
 	CFLAGS = -O0 $(INCLUDES) -Wall -DDEBUG
 	LDFLAGS = -shared
@@ -64,6 +66,10 @@ endif
 ifeq ($(TARGET), Emscripten)
 	CFLAGS +=
 	LDFLAGS += -lc -lm -ldl
+	ifeq ($(PTHREAD), 1)
+		CFLAGS += -pthread
+		LDFLAGS += -pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB
+	endif
 	CC = emcc
 	AR = emar
 endif
diff --git a/libhxcfe/build/Makefile b/libhxcfe/build/Makefile
index 07bee898..14276972 100644
--- a/libhxcfe/build/Makefile
+++ b/libhxcfe/build/Makefile
@@ -12,6 +12,8 @@ DEBUG ?= 0
 DEBUG_ASAN ?= 0
 DEBUG_INFOS ?= 0
 
+PTHREAD ?= 0
+
 ifeq ($(DEBUG), 1)
 	CFLAGS = -O0 $(INCLUDES) -Wall -DDEBUG
 	LDFLAGS = -shared
@@ -79,6 +81,12 @@ ifeq ($(TARGET), Emscripten)
 	CC = emcc
 	AR = emar
 	EXEC = libhxcfe.a
+	CFLAGS +=
+	LDFLAGS +=
+	ifeq ($(PTHREAD), 1)
+		CFLAGS += -pthread
+		LDFLAGS += -pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB
+	endif
 endif
 
 XML_DSKLAYOUT_INPUTS  := $(wildcard $(BASEDIR)/xml_disk/DiskLayouts/xml_files/DiskLayout_*.xml)
diff --git a/libusbhxcfe/build/Makefile b/libusbhxcfe/build/Makefile
index 33f4a1e9..c5df1ab2 100644
--- a/libusbhxcfe/build/Makefile
+++ b/libusbhxcfe/build/Makefile
@@ -11,6 +11,8 @@ DEBUG ?= 0
 DEBUG_ASAN ?= 0
 DEBUG_INFOS ?= 0
 
+PTHREAD ?= 0
+
 ifeq ($(DEBUG), 1)
 	CFLAGS = -O0 $(INCLUDES) -Wall -DDEBUG
 	LDFLAGS = -shared
@@ -71,6 +73,10 @@ endif
 ifeq ($(TARGET), Emscripten)
 	CFLAGS +=
 	LDFLAGS += -lc -lm -ldl
+	ifeq ($(PTHREAD), 1)
+		CFLAGS += -pthread
+		LDFLAGS += -pthread -sPTHREAD_POOL_SIZE=4 -sTOTAL_MEMORY=64MB
+	endif
 	CC = emcc
 	AR = emar
 	EXEC=libusbhxcfe.a