diff --git a/tools/emul/Makefile b/tools/emul/Makefile
index e1412b3..f92ed2a 100644
--- a/tools/emul/Makefile
+++ b/tools/emul/Makefile
@@ -1,27 +1,26 @@
 TARGETS = shell/shell zasm/zasm runbin/runbin
-KERNEL_HEADERS = shell/kernel.h zasm/kernel.h
-USER_HEADERS = zasm/user.h
 CFSPACK = ../cfspack/cfspack
 KERNEL = ../../kernel
 APPS = ../../apps
+ZASMBIN = zasm/zasm
 
 .PHONY: all
 all: $(TARGETS)
 
 shell/kernel.h: shell/shell_.asm
-zasm/kernel.h: zasm/glue.asm
-$(KERNEL_HEADERS):
 	scas -o - -I $(KERNEL) $< | ./bin2c.sh KERNEL | tee $@ > /dev/null
 
-zasm/user.h: $(APPS)/zasm/glue.asm
-$(USER_HEADERS):
-	scas -o - -I $(APPS) $< | ./bin2c.sh USERSPACE | tee $@ > /dev/null
+zasm/kernel.h: zasm/kernel.bin
+	./bin2c.sh KERNEL < $< | tee $@ > /dev/null
+
+zasm/user.h: zasm/zasm.bin
+	./bin2c.sh USERSPACE < $< | tee $@ > /dev/null
 
 zasm/includes.cfs: $(CFSPACK)
 	rm -rf zasm/includes
 	cp -r $(KERNEL) zasm/includes
 	cp -r $(APPS)/zasm zasm/includes/zasm
-	find zasm/includes -name *.md -o -name *.example -delete
+	find zasm/includes -name *.md -o -name *.example -o -name glue.asm -delete
 	find zasm/includes -type f -exec sed -i -e 's/;.*//g' {} \;
 	cp user.h zasm/includes
 	$(CFSPACK) zasm/includes > $@
@@ -31,7 +30,7 @@ zasm/includes.h: zasm/includes.cfs
 	./bin2c.sh FSDEV < $< | tee $@ > /dev/null
 	
 shell/shell: shell/shell.c libz80/libz80.o shell/kernel.h $(CFSPACK)
-zasm/zasm: zasm/zasm.c libz80/libz80.o zasm/kernel.h zasm/user.h zasm/includes.h
+$(ZASMBIN): zasm/zasm.c libz80/libz80.o zasm/kernel.h zasm/user.h zasm/includes.h
 runbin/runbin: runbin/runbin.c libz80/libz80.o
 $(TARGETS):
 	cc $< libz80/libz80.o -o $@
@@ -43,6 +42,11 @@ libz80/libz80.o: libz80/z80.c
 $(CFSPACK):
 	make -C ../cfspack
 
+.PHONY: updatebootstrap
+updatebootstrap: $(ZASMBIN)
+	$(ZASMBIN) < zasm/glue.asm > zasm/kernel.bin
+	$(ZASMBIN) < $(APPS)/zasm/glue.asm > zasm/zasm.bin
+
 .PHONY: clean
 clean:
-	rm -f $(TARGETS) $(KERNEL_HEADERS) $(USER_HEADERS) zasm/includes.*
+	rm -f $(TARGETS) zasm/{kernel,user}.h shell/kernel.h zasm/includes.*
diff --git a/tools/emul/README.md b/tools/emul/README.md
index 37cfe2a..77ec404 100644
--- a/tools/emul/README.md
+++ b/tools/emul/README.md
@@ -13,6 +13,18 @@ We don't try to emulate real hardware to ease the development of device drivers
 because so far, I don't see the advantage of emulation versus running code on
 the real thing.
 
+## Bootstrapped binary
+
+The file `zasm/zasm.bin` is a compiled binary for `apps/zasm/glue.asm`. It is
+used to bootstrap the assembling process so that no assembler other than zasm
+is required to build Collapse OS.
+
+This binary is fed to libz80 to produce the `zasm/zasm` "modern" binary and
+once you have that, you can recreate `zasm/zasm.bin`.
+
+This is why it's included as a binary in the repo, but yes, it's redundant with
+the source code.
+
 ## Usage
 
 First, make sure that the `libz80` git submodule is checked out. If not, run
diff --git a/tools/emul/zasm/glue.asm b/tools/emul/zasm/glue.asm
index d8d8a24..1b2c2c5 100644
--- a/tools/emul/zasm/glue.asm
+++ b/tools/emul/zasm/glue.asm
@@ -1,5 +1,6 @@
 ; Glue code for the emulated environment
 .equ RAMSTART		0x4000
+.equ USER_CODE		0x4800
 .equ STDIO_PORT		0x00
 .equ STDIN_SEEK		0x01
 .equ FS_DATA_PORT	0x02
@@ -39,7 +40,6 @@ jp     fsTell
 .equ	FS_RAMSTART	BLOCKDEV_RAMEND
 .equ	FS_HANDLE_COUNT	0
 #include "fs.asm"
-#include "user.h"
 
 init:
 	di
diff --git a/tools/emul/zasm/kernel.bin b/tools/emul/zasm/kernel.bin
new file mode 100644
index 0000000..e2e5782
Binary files /dev/null and b/tools/emul/zasm/kernel.bin differ
diff --git a/tools/emul/zasm/zasm.bin b/tools/emul/zasm/zasm.bin
new file mode 100644
index 0000000..2ed59ed
Binary files /dev/null and b/tools/emul/zasm/zasm.bin differ