Index: tools/mkhord.py
===================================================================
--- tools/mkhord.py	(revision 8c25a4ab901eeb3ee0eb25b1c0b5d5ffda31cc36)
+++ tools/mkhord.py	(revision b3105ff6d7483bc6e5d9bf19f64b6178a15304ea)
@@ -34,4 +34,16 @@
 import os
 import struct
+import xstruct
+
+HEADER = xstruct.convert("little: "
+	"char[4]   /* 'HORD' */ "
+	"uint8_t   /* version */ "
+	"uint8_t   /* encoding */ "
+	"uint32_t  /* header size */ "
+	"uint64_t  /* payload size */ "
+)
+
+HORD_VERSION = 1
+HORD_LSB = 1
 
 def align_up(size, alignment):
@@ -53,4 +65,8 @@
 	
 	align = int(sys.argv[1], 0)
+	if (align <= 0):
+		print "<ALIGNMENT> must be positive"
+		return
+	
 	fs_image = os.path.abspath(sys.argv[2])
 	if (not os.path.isfile(fs_image)):
@@ -61,15 +77,18 @@
 	outf = file(sys.argv[3], "wb")
 	
-	header_size = align_up(18, align)
-	aligned_size = align_up(os.path.getsize(fs_image), align)
+	header_size = struct.calcsize(HEADER)
+	payload_size = os.path.getsize(fs_image)
 	
-	outf.write(struct.pack("<4sBBLQ", "HORD", 1, 1, header_size, aligned_size))
-	outf.write(struct.pack("<" + ("%d" % (header_size - 18)) + "x"))
+	header_size_aligned = align_up(header_size, align)
+	payload_size_aligned = align_up(payload_size, align)
+	
+	outf.write(struct.pack(HEADER, "HORD", HORD_VERSION, HORD_LSB, header_size_aligned, payload_size_aligned))
+	outf.write(xstruct.little_padding(header_size_aligned - header_size))
 	
 	outf.write(inf.read())
 	
-	padding = aligned_size - os.path.getsize(fs_image)
+	padding = payload_size_aligned - payload_size
 	if (padding > 0):
-		outf.write(struct.pack("<" + ("%d" % padding) + "x"))
+		outf.write(xstruct.little_padding(padding))
 	
 	inf.close()
Index: tools/mktmpfs.py
===================================================================
--- tools/mktmpfs.py	(revision 8c25a4ab901eeb3ee0eb25b1c0b5d5ffda31cc36)
+++ tools/mktmpfs.py	(revision b3105ff6d7483bc6e5d9bf19f64b6178a15304ea)
@@ -36,7 +36,16 @@
 import xstruct
 
-HEADER = xstruct.convert("little: char[5]")
-DENTRY = xstruct.convert("little: uint8_t uint32_t")
-SIZE = xstruct.convert("little: uint32_t")
+HEADER = xstruct.convert("little: "
+	"char[5]  /* 'TMPFS' */ "
+)
+
+DENTRY = xstruct.convert("little: "
+	"uint8_t   /* NONE, FILE or DIRECTORY */ "
+	"uint32_t  /* filename length */ "
+)
+
+SIZE = xstruct.convert("little: "
+	"uint32_t  /* file size */ "
+)
 
 DENTRY_NONE = 0
Index: tools/xstruct.py
===================================================================
--- tools/xstruct.py	(revision 8c25a4ab901eeb3ee0eb25b1c0b5d5ffda31cc36)
+++ tools/xstruct.py	(revision b3105ff6d7483bc6e5d9bf19f64b6178a15304ea)
@@ -43,9 +43,17 @@
 		"network:": lambda: "!"
 	}[tokens[0]]()
-		
+	
 	# Member tags
 	
+	comment = False
 	for token in tokens[1:]:
-		if (token[0:5] == "char["):
+		if (comment):
+			if (token == "*/"):
+				comment = False
+			continue
+		
+		if (token == "/*"):
+			comment = True
+		elif (token[0:5] == "char["):
 			size = token[5:].split("]")[0]
 			struct += ("%d" % int(size)) + "s"
@@ -67,2 +75,5 @@
 def little_string(string):
 	return struct.pack("<" + ("%d" % len(string)) + "s", string)
+
+def little_padding(length):
+	return struct.pack("<" + ("%d" % length) + "x")