diff --git a/testcode/lib/atari/Makefile b/testcode/lib/atari/Makefile
new file mode 100644
index 000000000..e9ec853b8
--- /dev/null
+++ b/testcode/lib/atari/Makefile
@@ -0,0 +1,32 @@
+
+all: charmapping.xex defdev.xex displaylist.xex mem.xex multi.xex ostype.xex \
+	scrcode.com sys.xex
+
+charmapping.xex: charmapping.c
+	cl65 -t atari -o charmapping.xex charmapping.c
+defdev.xex: defdev.c
+	cl65 -t atari -o defdev.xex defdev.c
+displaylist.xex: displaylist.c
+	cl65 -t atari -o displaylist.xex displaylist.c
+mem.xex: mem.c ../getsp.s
+	cl65 -t atari -o mem.xex mem.c ../getsp.s
+multi.xex: multi-xex.s multi-xex.cfg
+	cl65 -t atari -C multi-xex.cfg multi-xex.s -o multi.xex
+ostype.xex: ostype.c
+	cl65 -t atari -o ostype.xex ostype.c
+scrcode.com: scrcode.s
+	ca65 -t atari -o scrcode.o scrcode.s
+	ld65 -C atari-asm.cfg -o scrcode.com scrcode.o
+sys.xex: sys.c
+	cl65 -t atari -o sys.xex sys.c
+
+clean:
+	$(RM) charmapping.xex
+	$(RM) defdev.xex
+	$(RM) displaylist.xex
+	$(RM) mem.xex
+	$(RM) multi.xex
+	$(RM) ostype.xex
+	$(RM) scrcode.o
+	$(RM) scrcode.com
+	$(RM) sys.xex
diff --git a/testcode/lib/atari/multi.xex b/testcode/lib/atari/multi.xex
deleted file mode 100644
index 7da39ad47..000000000
Binary files a/testcode/lib/atari/multi.xex and /dev/null differ
diff --git a/testcode/lib/atari/scrcode.s b/testcode/lib/atari/scrcode.s
index cd4290781..ba778579b 100644
--- a/testcode/lib/atari/scrcode.s
+++ b/testcode/lib/atari/scrcode.s
@@ -43,15 +43,20 @@ key:            lda     CH
 dispdata:       scrcode         "fooBa", 'r', $66, 3+4
 disp_len        =       * - dispdata
 
+.export         __AUTOSTART__: absolute = 1
 .segment        "AUTOSTRT"
 
                 .word   $02E0
                 .word   $02E1
                 .word   __CODE_LOAD__+1
 
+.export         __EXEHDR__: absolute = 1
 .segment        "EXEHDR"
 
                 .word   $FFFF
+
+.segment        "MAINHDR"
+
                 .word   __CODE_LOAD__
                 .word   __BSS_LOAD__ - 1
 
diff --git a/testcode/lib/atari/sys.c b/testcode/lib/atari/sys.c
index 9ec7aa631..59debd758 100644
--- a/testcode/lib/atari/sys.c
+++ b/testcode/lib/atari/sys.c
@@ -10,6 +10,8 @@
 #include <6502.h>
 #include <conio.h>
 
+#define IOCB    (OS.iocb[0])
+
 static struct regs regs;
 static struct __iocb *iocb = &IOCB;  /* use IOCB #0 */