diff --git a/GenerateCDT/GenerateCDT.py b/GenerateCDT/GenerateCDT.py
index 08874b5..10b9bc4 100755
--- a/GenerateCDT/GenerateCDT.py
+++ b/GenerateCDT/GenerateCDT.py
@@ -6,8 +6,8 @@
 
 
 def main():
-	if (len(sys.argv) != 4):
-		print "Usage: %s datafile outfile zero_duration" % sys.argv[0]
+	if (len(sys.argv) != 4 and len(sys.argv) != 5):
+		print "Usage: %s datafile outfile zero_duration [loaderfile]" % sys.argv[0]
 		return
 
 	zeroBitLength = int(sys.argv[3])
@@ -18,10 +18,24 @@ def main():
 	oneBitLengthLow = oneBitLength & 0xFF
 	oneBitLengthHigh = (oneBitLength >> 8) & 0xFF
 
-
+	if len(sys.argv) == 5:
+		loaderFileName = sys.argv[4]
+		with open(loaderFileName, mode='rb') as fin:
+			loaderContent = bytearray(fin.read())
+		fin.close()
+		loaderLength = len(loaderContent)
+		loaderLengthLow = loaderLength & 0xFF
+		loaderLengthHigh = (loaderLength >> 8) & 0xFF
+		loaderSegments = loaderLength // 256 + 1				# Calculate number of 256 byte segments required
+		loaderBlockLength = loaderSegments * 258 +5				# Caclulate block length (data + flags + checksums + trailer)
+		for i in range(loaderSegments * 256 - loaderLength):	# Pad loader up to the next 256 byte boundary with zeroes
+			loaderContent.append(0x00)
+		loaderBlockLengthLow = loaderBlockLength & 0xFF
+		loaderBlockLengthHigh = (loaderBlockLength >> 8) & 0xFF	
+	
 	dataFileName = sys.argv[1]
 	with open(dataFileName, mode='rb') as fin:
-		fileContent = fin.read()
+		fileContent = bytearray(fin.read())
 	fin.close()
 	contentLength = len(fileContent)
 	contentLengthLow = contentLength & 0xFF
@@ -30,7 +44,97 @@ def main():
 	data = bytearray('ZXTape!')
 	data.append(0x1A)
 	# Version
-	data.extend([0x01, 0x0D])
+	data.extend([0x01, 0x14])
+
+	# Standard CPC header block
+	# TZX header
+	if len(sys.argv) == 5:
+		data.append(0x11)			# Block ID
+		data.append(0x21)			# Pilot pulse length (L)
+		data.append(0x0B)			# Pilot pulse length (H)
+		data.append(0xAD)			# Sync1 pulse length (L)
+		data.append(0x05)			# Sync1 pulse length (H)
+		data.append(0xAD)			# Sync2 pulse length (L)
+		data.append(0x05)			# Sync2 pulse length (H)
+		data.append(0xA2)			# Zero pulse length (L)
+		data.append(0x05)			# Zero pulse length (H)
+		data.append(0x05)			# One pulse length (L)
+		data.append(0x0B)			# One pulse length (H)
+		data.append(0x02)			# Pilot pulse count (L)
+		data.append(0x10)			# Pilot pulse count (H)
+		data.append(0x08)			# Bits used in last byte
+		data.append(0x11)			# Pause after this block (L)
+		data.append(0x00)			# Pause after this block (H)
+		data.append(0x07)			# Data length (L)
+		data.append(0x01)			# Data length (M)
+		data.append(0x00)			# Data length (H)
+	# CPC header
+		data.append(0x2c)			# Flag (0x2c for header, 0x16 for data)
+		data.extend([0x48, 0x59, 0x50, 0x45,\
+					 0x52, 0x4C, 0x4F, 0x41,\
+					 0x44, 0x45, 0x52, 0x00,\
+					 0x00, 0x00, 0x00, 0x00])	# Filename ("HYPERLOADER" padded to 16 bytes with zeroes)
+		data.append(0x01)			# Block number
+		data.append(0xFF)			# Last block indicator (non-zero = last block)
+		data.append(0x02)			# File type
+									#	Bits 1-3 determine file type:-
+									#		0	BASIC
+									#		1	Binary
+									#		2	Screen Image
+									#		3	ASCII
+									#		4-7	Unused
+		data.append(loaderLengthLow)	# Data length (L)
+		data.append(loaderLengthHigh)	# Data length (H)
+		data.append(0x00)			# Destination address (L)
+		data.append(0x40)			# Destination address (H)
+		data.append(0xFF)			# First block indicator (non-zero = first block)
+		data.append(loaderLengthLow)	# File length (L)
+		data.append(loaderLengthHigh)	# File length (H)
+		data.append(0x00)			# Exec address (L)
+		data.append(0x40)			# Exec address (H)
+		for i in range(228):		
+			data.append(0x00)		# Pad up to 256 bytes with zeroes
+		data.append(0xD2)			# Checksum (H)
+		data.append(0x00)			# Checksum (L)
+		data.extend([0xFF, 0xFF, 0xFF, 0xFF])	#	Trailer
+
+	# Standard CPC data block
+	# TZX Header
+		data.append(0x11)			# Block ID
+		data.append(0x21)			# Pilot pulse length (L)
+		data.append(0x0B)			# Pilot pulse length (H)
+		data.append(0xA6)			# Sync1 pulse length (L)
+		data.append(0x05)			# Sync1 pulse length (H)
+		data.append(0xA6)			# Sync2 pulse length (L)
+		data.append(0x05)			# Sync2 pulse length (H)
+		data.append(0x8B)			# Zero pulse length (L)
+		data.append(0x05)			# Zero pulse length (H)
+		data.append(0x1D)			# One pulse length (L)
+		data.append(0x0B)			# One pulse length (H)
+		data.append(0x02)			# Pilot pulse count (L)
+		data.append(0x10)			# Pilot pulse count (H)
+		data.append(0x08)			# Bits used in last byte
+		data.append(0x78)			# Pause after this block (L)
+		data.append(0x11)			# Pause after this block (H)
+		data.append(loaderBlockLengthLow)	# Data length (L)
+		data.append(loaderBlockLengthHigh)	# Data length (M)
+		data.append(0x00)			# Data length (H)
+	# CPC Data
+		data.append(0x16)			# Flag
+		for i in range(loaderSegments):
+			crc = 0xFFFF								# CRC initial seed
+			for j in range(256):
+				data.append(loaderContent[j])			# Add byte from loader
+				k = crc >> 8 ^ loaderContent[j]			# CRC iteration
+				k = k ^ k >> 4
+				crc = crc << 8 ^ k << 12 ^ k << 5 ^ k
+				crc	= crc & 0xFFFF
+			crc = crc ^ 0xFFFF							# One's complement for final CRC value
+			crcHigh = crc >> 8 & 0xFF
+			crcLow = crc & 0xFF
+			data.append(crcHigh)	# Checksum (H)
+			data.append(crcLow)		# Checksum (L)
+		data.extend([0xFF, 0xFF, 0xFF, 0xFF])	#	Trailer
 
 	# Block group
 	data.append(0x21)			# Block ID
@@ -40,8 +144,8 @@ def main():
 	data.append(0x12)			# Block ID
 	data.append(0x22)			# Pulse length (L)
 	data.append(0x0B)			# Pulse length (H)
-	data.append(0xFF)			# Pulse count (L)
-	data.append(0x03)			# Pulse count (H)
+	data.append(0x00)			# Pulse count (L)
+	data.append(0x04)			# Pulse count (H)
 
 	# Pure tone 2
 	data.append(0x12)			# Block ID