diff --git a/apps/zasm/main.asm b/apps/zasm/main.asm
index ca258dd..2f32cf0 100644
--- a/apps/zasm/main.asm
+++ b/apps/zasm/main.asm
@@ -27,11 +27,14 @@ zasmMain:
 	ld	de, .argspecs
 	ld	ix, ZASM_RAMSTART
 	call	parseArgs
+	jr	z, .goodargs
+	; bad args
 	ld	hl, 0
 	ld	de, 0
 	ld	a, SHELL_ERR_BAD_ARGS
-	ret	nz
+	ret
 
+.goodargs:
 	; HL now points to parsed args
 	; Init I/O
 	ld	a, (ZASM_RAMSTART)	; blkdev in ID
diff --git a/tools/emul/.gitignore b/tools/emul/.gitignore
index d0ec041..9527004 100644
--- a/tools/emul/.gitignore
+++ b/tools/emul/.gitignore
@@ -1,8 +1,6 @@
 /shell/shell
 /zasm/zasm
 /runbin/runbin
-/zasm/includes.*
-/*/kernel.h
-/*/user.h
+/*/*-bin.h
 /cfsin
 /cfsout
diff --git a/tools/emul/Makefile b/tools/emul/Makefile
index a92776c..f30a250 100644
--- a/tools/emul/Makefile
+++ b/tools/emul/Makefile
@@ -8,17 +8,17 @@ ZASMSH = ../zasm.sh
 .PHONY: all
 all: $(TARGETS)
 
-shell/kernel.h: shell/shell_.asm $(ZASMBIN)
+shell/kernel-bin.h: shell/shell_.asm $(ZASMBIN)
 	$(ZASMSH) $(KERNEL) < $< | ./bin2c.sh KERNEL | tee $@ > /dev/null
 
-zasm/kernel.h: zasm/kernel.bin
+zasm/kernel-bin.h: zasm/kernel.bin
 	./bin2c.sh KERNEL < $< | tee $@ > /dev/null
 
-zasm/user.h: zasm/zasm.bin
+zasm/zasm-bin.h: zasm/zasm.bin
 	./bin2c.sh USERSPACE < $< | tee $@ > /dev/null
 
-shell/shell: shell/shell.c libz80/libz80.o shell/kernel.h 
-$(ZASMBIN): zasm/zasm.c libz80/libz80.o zasm/kernel.h zasm/user.h $(CFSPACK)
+shell/shell: shell/shell.c libz80/libz80.o shell/kernel-bin.h 
+$(ZASMBIN): zasm/zasm.c libz80/libz80.o zasm/kernel-bin.h zasm/zasm-bin.h $(CFSPACK)
 runbin/runbin: runbin/runbin.c libz80/libz80.o
 $(TARGETS):
 	$(CC) $< libz80/libz80.o -o $@
@@ -33,7 +33,7 @@ $(CFSPACK):
 .PHONY: updatebootstrap
 updatebootstrap: $(ZASMBIN) $(INCCFS)
 	$(ZASMSH) $(KERNEL) < zasm/glue.asm > zasm/kernel.bin
-	$(ZASMSH) $(KERNEL) $(APPS) user.h < $(APPS)/zasm/glue.asm > zasm/zasm.bin
+	$(ZASMSH) $(KERNEL) $(APPS) zasm/user.h < $(APPS)/zasm/glue.asm > zasm/zasm.bin
 
 # Sometimes, when developing zasm, stuff get messed up and it's hard to unmess
 # because zasm's brake-up ends up in its bootstrap bins. Sure, we can revert
@@ -42,8 +42,8 @@ updatebootstrap: $(ZASMBIN) $(INCCFS)
 .PHONY: rescue
 rescue:
 	scas -o zasm/kernel.bin -I $(KERNEL) zasm/glue.asm
-	scas -o zasm/zasm.bin -I $(APPS) -I $(KERNEL) $(APPS)/zasm/glue.asm
+	scas -o zasm/zasm.bin -I $(APPS) -I $(KERNEL) -I zasm $(APPS)/zasm/glue.asm
 
 .PHONY: clean
 clean:
-	rm -f $(TARGETS) zasm/{kernel,user}.h shell/kernel.h zasm/includes.*
+	rm -f $(TARGETS) {zasm,shell}/*-bin.h
diff --git a/tools/emul/shell/shell.c b/tools/emul/shell/shell.c
index 9459b73..8193e9d 100644
--- a/tools/emul/shell/shell.c
+++ b/tools/emul/shell/shell.c
@@ -2,7 +2,7 @@
 #include <stdio.h>
 #include <termios.h>
 #include "../libz80/z80.h"
-#include "kernel.h"
+#include "kernel-bin.h"
 
 /* Collapse OS shell with filesystem
  *
diff --git a/tools/emul/user.h b/tools/emul/zasm/user.h
similarity index 100%
rename from tools/emul/user.h
rename to tools/emul/zasm/user.h
diff --git a/tools/emul/zasm/zasm.c b/tools/emul/zasm/zasm.c
index bba87aa..b858c99 100644
--- a/tools/emul/zasm/zasm.c
+++ b/tools/emul/zasm/zasm.c
@@ -1,8 +1,8 @@
 #include <stdint.h>
 #include <stdio.h>
 #include "../libz80/z80.h"
-#include "kernel.h"
-#include "user.h"
+#include "kernel-bin.h"
+#include "zasm-bin.h"
 
 /* zasm reads from a specified blkdev, assemble the file and writes the result
  * in another specified blkdev. In our emulator layer, we use stdin and stdout