diff --git a/recipes/rc2014/Makefile b/recipes/rc2014/Makefile
index c51b706..d51a00f 100644
--- a/recipes/rc2014/Makefile
+++ b/recipes/rc2014/Makefile
@@ -1,5 +1,5 @@
 TARGET = os.bin
-ZASM = ../../tools/emul/zasm/zasm
+ZASM = ../../tools/zasm.sh
 
 .PHONY: all
 all: $(TARGET)
diff --git a/recipes/rc2014/glue.asm b/recipes/rc2014/glue.asm
index da1c3ed..fd3fe08 100644
--- a/recipes/rc2014/glue.asm
+++ b/recipes/rc2014/glue.asm
@@ -11,6 +11,7 @@ jp	init
 .fill	0x38-$
 jp	aciaInt
 
+#include "err.h"
 #include "core.asm"
 #include "parse.asm"
 .equ	ACIA_RAMSTART	RAMSTART
diff --git a/recipes/rc2014/sdcard/Makefile b/recipes/rc2014/sdcard/Makefile
index d408c7e..906742d 100644
--- a/recipes/rc2014/sdcard/Makefile
+++ b/recipes/rc2014/sdcard/Makefile
@@ -1,6 +1,6 @@
 TARGETS = os.bin cfsin/helo
 TOOLS = ../../../tools
-ZASM = $(TOOLS)/emul/zasm/zasm
+ZASM = $(TOOLS)/zasm.sh
 CFSPACK = $(TOOLS)/cfspack/cfspack
 
 .PHONY: all
diff --git a/recipes/rc2014/sdcard/README.md b/recipes/rc2014/sdcard/README.md
index 1695839..17a8018 100644
--- a/recipes/rc2014/sdcard/README.md
+++ b/recipes/rc2014/sdcard/README.md
@@ -1,7 +1,5 @@
 # Accessing a MicroSD card
 
-**Status: work in progress.**
-
 SD cards are great because they are accessible directly. No supporting IC is
 necessary. The easiest way to access them is through the SPI protocol.
 
diff --git a/recipes/rc2014/sdcard/glue.asm b/recipes/rc2014/sdcard/glue.asm
index 8e81a5e..36ff7c8 100644
--- a/recipes/rc2014/sdcard/glue.asm
+++ b/recipes/rc2014/sdcard/glue.asm
@@ -20,6 +20,7 @@ jp	sdcSendRecv
 .fill	0x38-$
 jp	aciaInt
 
+#include "err.h"
 #include "core.asm"
 #include "parse.asm"
 .equ	ACIA_RAMSTART	RAMSTART
diff --git a/tools/emul/Makefile b/tools/emul/Makefile
index 0ccfa52..7e1ab12 100644
--- a/tools/emul/Makefile
+++ b/tools/emul/Makefile
@@ -3,12 +3,13 @@ CFSPACK = ../cfspack/cfspack
 KERNEL = ../../kernel
 APPS = ../../apps
 ZASMBIN = zasm/zasm
+INCCFS = zasm/includes.cfs
 
 .PHONY: all
 all: $(TARGETS)
 
-shell/kernel.h: shell/shell_.asm $(ZASMBIN)
-	$(ZASMBIN) < $< | ./bin2c.sh KERNEL | tee $@ > /dev/null
+shell/kernel.h: shell/shell_.asm $(ZASMBIN) $(INCCFS)
+	$(ZASMBIN) $(INCCFS) < $< | ./bin2c.sh KERNEL | tee $@ > /dev/null
 
 zasm/kernel.h: zasm/kernel.bin
 	./bin2c.sh KERNEL < $< | tee $@ > /dev/null
@@ -16,7 +17,7 @@ zasm/kernel.h: zasm/kernel.bin
 zasm/user.h: zasm/zasm.bin
 	./bin2c.sh USERSPACE < $< | tee $@ > /dev/null
 
-zasm/includes.cfs: $(CFSPACK)
+$(INCCFS): $(CFSPACK)
 	rm -rf zasm/includes
 	cp -r $(KERNEL) zasm/includes
 	cp -r $(APPS)/zasm zasm/includes/zasm
@@ -26,11 +27,8 @@ zasm/includes.cfs: $(CFSPACK)
 	$(CFSPACK) zasm/includes > $@
 	rm -rf zasm/includes
 
-zasm/includes.h: zasm/includes.cfs
-	./bin2c.sh FSDEV < $< | tee $@ > /dev/null
-	
 shell/shell: shell/shell.c libz80/libz80.o shell/kernel.h $(CFSPACK)
-$(ZASMBIN): 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
 runbin/runbin: runbin/runbin.c libz80/libz80.o
 $(TARGETS):
 	$(CC) $< libz80/libz80.o -o $@
@@ -43,9 +41,9 @@ $(CFSPACK):
 	make -C ../cfspack
 
 .PHONY: updatebootstrap
-updatebootstrap: $(ZASMBIN)
-	$(ZASMBIN) < zasm/glue.asm > zasm/kernel.bin
-	$(ZASMBIN) < $(APPS)/zasm/glue.asm > zasm/zasm.bin
+updatebootstrap: $(ZASMBIN) $(INCCFS)
+	$(ZASMBIN) $(INCCFS) < zasm/glue.asm > zasm/kernel.bin
+	$(ZASMBIN) $(INCCFS) < $(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
diff --git a/tools/emul/zasm/zasm.c b/tools/emul/zasm/zasm.c
index c91f6d7..c77ee08 100644
--- a/tools/emul/zasm/zasm.c
+++ b/tools/emul/zasm/zasm.c
@@ -3,12 +3,14 @@
 #include "../libz80/z80.h"
 #include "kernel.h"
 #include "user.h"
-#include "includes.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
  * as those specified blkdevs.
  *
+ * This executable takes one argument: the path to a .cfs file to use for
+ * includes.
+ *
  * Because the input blkdev needs support for Seek, we buffer it in the emulator
  * layer.
  *
@@ -152,8 +154,12 @@ static void mem_write(int unused, uint16_t addr, uint8_t val)
     mem[addr] = val;
 }
 
-int main()
+int main(int argc, char *argv[])
 {
+    if (argc > 2) {
+        fprintf(stderr, "Too many args\n");
+        return 1;
+    }
     // initialize memory
     for (int i=0; i<sizeof(KERNEL); i++) {
         mem[i] = KERNEL[i];
@@ -161,10 +167,21 @@ int main()
     for (int i=0; i<sizeof(USERSPACE); i++) {
         mem[i+USER_CODE] = USERSPACE[i];
     }
-    for (int i=0; i<sizeof(FSDEV); i++) {
-        fsdev[i] = FSDEV[i];
+    fsdev_size = 0;
+    if (argc == 2) {
+        FILE *fp = fopen(argv[1], "r");
+        if (fp == NULL) {
+            fprintf(stderr, "Can't open file %s\n", argv[1]);
+            return 1;
+        }
+        int c = fgetc(fp);
+        while (c != EOF) {
+            fsdev[fsdev_size] = c;
+            fsdev_size++;
+            c = fgetc(fp);
+        }
+        fclose(fp);
     }
-    fsdev_size = sizeof(FSDEV);
     // read stdin in buffer
     inpt_size = 0;
     inpt_ptr = 0;
diff --git a/tools/tests/unit/runtests.sh b/tools/tests/unit/runtests.sh
index 65113db..8dec42e 100755
--- a/tools/tests/unit/runtests.sh
+++ b/tools/tests/unit/runtests.sh
@@ -3,7 +3,7 @@
 set -e
 set -o pipefail
 
-ZASM=../../emul/zasm/zasm
+ZASM=../../zasm.sh
 RUNBIN=../../emul/runbin/runbin
 
 for fn in *.asm; do
diff --git a/tools/tests/zasm/errtests.sh b/tools/tests/zasm/errtests.sh
index 834f8a0..89ad1fa 100755
--- a/tools/tests/zasm/errtests.sh
+++ b/tools/tests/zasm/errtests.sh
@@ -2,7 +2,7 @@
 
 # no "set -e" because we test errors
 
-ZASM=../../emul/zasm/zasm
+ZASM=../../zasm.sh
 
 chkerr() {
     echo "Check that '$1' results in error $2"
diff --git a/tools/tests/zasm/runtests.sh b/tools/tests/zasm/runtests.sh
index a97c8e2..eca3014 100755
--- a/tools/tests/zasm/runtests.sh
+++ b/tools/tests/zasm/runtests.sh
@@ -6,7 +6,7 @@ TMPFILE=$(mktemp)
 SCAS=scas
 KERNEL=../../../kernel
 APPS=../../../apps
-ZASM=../../emul/zasm/zasm
+ZASM=../../zasm.sh
 ASMFILE=${APPS}/zasm/instr.asm
 
 cmpas() {
diff --git a/tools/zasm.sh b/tools/zasm.sh
new file mode 100755
index 0000000..8d835f5
--- /dev/null
+++ b/tools/zasm.sh
@@ -0,0 +1,7 @@
+#!/bin/bash
+
+# wrapper around ./emul/zasm/zasm that prepares includes CFS prior to call
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+ZASMBIN="${DIR}/emul/zasm/zasm"
+INCCFS="${DIR}/emul/zasm/includes.cfs"
+"${ZASMBIN}" "${INCCFS}"