diff --git a/.gitignore b/.gitignore
index fe93128..3d3cb35 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.tap
-*bin
-*bincs
+*.block
+body
+header
 ttttt
diff --git a/Makefile b/Makefile
index d255a68..69235f3 100644
--- a/Makefile
+++ b/Makefile
@@ -2,15 +2,15 @@ program.tap: header.block body.block
 	cat header.block body.block > program.tap
 
 header.block: header ttttt
-	./ttttt header
+	./ttttt header header
 
 header: header.asm body.block
 	pasmo header.asm headerlong
-	dd if=headerlong of=header bs=18 count=1
+	dd if=headerlong of=header bs=17 count=1
 	rm -f headerlong
 
 body.block: body ttttt
-	./ttttt body
+	./ttttt body data
 
 body: remload.asm code.asm
 	pasmo remload.asm body
diff --git a/header.asm b/header.asm
index 6d13bfa..468b85c 100644
--- a/header.asm
+++ b/header.asm
@@ -1,6 +1,3 @@
-headerflag:
-	db 0
-
 blocktype:
 	db 0		;basic program
 
diff --git a/remload.asm b/remload.asm
index 14eaae6..07640dd 100644
--- a/remload.asm
+++ b/remload.asm
@@ -1,7 +1,5 @@
-org #5cca
+org #5ccb
 
-bodyformat:
-	db #ff
 linenumber:
 	db #00		;MSB
 	db #00		;LSB
diff --git a/ttttt.c b/ttttt.c
index 60c81cc..aded03f 100644
--- a/ttttt.c
+++ b/ttttt.c
@@ -15,13 +15,31 @@ int main(int argc, char *argv[])
 	int fdin, fdout;
 	char outfilename[PATH_MAX];
 	unsigned int count = 0;
+	unsigned char flagopt = 0;
 	unsigned char tally = 0;
 	unsigned char next = 0;
-	if (argc!=2) {
+	if ((argc<2) || (argc>3)) {
 		printf("Please specify file to read.\n");
 		return -1;
 	}
 
+	if (3==argc) {
+		if (!strcmp(argv[2], "header")) flagopt = 1;
+		if (!strcmp(argv[2], "data")) flagopt = 2;
+		if (!flagopt) {
+			printf("Optional flags are \"header\" or \"data\"\n");
+			return -1;
+		}
+	}
+
+	if (! flagopt) {
+		printf("*** WARNING ***\n");
+		printf("*** ttttt is running in RAW mode.\n");
+		printf("*** Have you manually included the format flag as the first byte of the block?\n");
+		printf("*** If not, run again passing 'header' or 'data' as the second parameter.\n");
+		printf("*** WARNING ***\n\n");
+	}
+
 	fdin = open(argv[1], O_RDONLY);
 	if (fdin<0) {
 		printf("Couldn't open %s. for reading\n", argv[1]);
@@ -49,10 +67,18 @@ int main(int argc, char *argv[])
 	};
 	lseek(fdin, 0, SEEK_SET);
 
+	if (flagopt) count++;
+
 	char lsb = (count+1)&255;
 	char msb = ((count+1)>>8)&255;
 	write(fdout, &lsb, 1);
 	write(fdout, &msb, 1);
+	next = 0;
+	if (flagopt == 2) next = 255;
+	if (flagopt) {
+		write(fdout, &next, 1);
+		tally ^= next;
+	}
 	while (read(fdin, &next, 1)) {
 		write(fdout, &next, 1);
 	}
@@ -62,8 +88,8 @@ int main(int argc, char *argv[])
 	close(fdin);
 
 	printf("File %s written.\n", outfilename);
-	printf("Code length including first byte is %d (0x%.4X).\n", count, count);
-	printf("Removing first byte gives 0x%.4X.\n", count-1);
+	count--;
+	printf("Code length is %d (0x%.4X).\n", count, count);
 
 	return 0;
 }