Windows NT will not load drivers that do not have a correct checksum.
 You can apply this patch to binutils to solve the problem:
 
 http://sources.redhat.com/ml/binutils/2002-01/msg00395.html
 
 It writes a checksum to a PE image.
 
 Alternatively you can search for a tool that will do the same and use it on 
 an image generated with MinGW.
 
 Here is an example of a makefile that will generate a .sys file that Windows 
 NT will load (if ld has the checksum patch applied).
 
 
 TOOLBASE = /usr/local/cross-tools/bin
 
 GCC = $(TOOLBASE)/i386-mingw32msv-gcc
 DLLTOOL = $(TOOLBASE)/i386-mingw32msv-dlltool
 
 BASENAME = null
 
 FULLNAME = $(BASENAME).sys
 CFLAGS = -I../
 
 OBJECTS = $(BASENAME).o
 
 DDKLIBS = ntoskrnl.a
 
 all: $(FULLNAME)
 
 $(FULLNAME): $(OBJECTS)
 	$(GCC) -Wl,--base-file,base.tmp \
 		-Wl,--entry,_DriverEntry \
 		-nostartfiles -nostdlib \
 		-o junk.tmp \
 		$(OBJECTS) $(DDKLIBS)
 	$(DLLTOOL) --dllname $(FULLNAME) \
 		--base-file base.tmp \
 		--output-exp temp.exp
 	$(GCC) $(TARGET_LFLAGS) \
                 	-Wl,--subsystem,native \
 		-Wl,--image-base,0x10000 \
 		-Wl,--file-alignment,0x1000 \
 		-Wl,--section-alignment,0x1000 \
 		-Wl,--entry,_DriverEntry \
 		-Wl,temp.exp \
 		-mdll -nostartfiles -nostdlib \
 		-o $(FULLNAME) \
 	  	$(OBJECTS) $(DDKLIBS)
 
 %.o: %.c
 	$(GCC) $(CFLAGS) -c $< -o $@

///////////////////////////////////////////////////////////////////////////////////////////////

 Is the use of DLLTOOL really needed ? I though ld could now generate the dll 
 relocation data automatically. Would this be enough:
 
 $(FULLNAME): $(OBJECTS)
 	$(GCC) $(TARGET_LFLAGS) \
                 	-Wl,--subsystem,native \
 		-Wl,--entry,_DriverEntry \
 		-shared -nostartfiles -nostdlib \
 		-o $(FULLNAME) \
 	  	$(OBJECTS) $(DDKLIBS)