ZISD Map
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Stored on primary HD, starting at 0xA00
(* may be elsewhere (up to at least 0x7A00) as of ZfD 6.5SP2)

0x00 - 0x03 = ZISD (literal text)
0x04 - 0x07 = version
0x08 - 0x0B = Total length of data [ie 0xA00 + this = byte after last]
0x0C - 0x0F = 3 (or 1?) when just imaged (ie, write the the ws info on next boot), else 2
0x10 - 0x13 = Uses DHCP (1 if yes)
0x14 - 0x17 = IP address
0x18 - 0x1B = Gateway
0x1C - 0x1F = Netmask
0x20 - 0x27 = Last image : Modification Date
0x28 - 0x2F = Last image : Size
0x30 - 0x33 = Start of text area - 0x48 for v3, 0xCC for v4
0x34 - 0x47 = SID
0x48 - 0xCB = 0 (v4)
0x48/0xCC - Textual details:

WS object , Tree name , Computer name , Workgroup, Last restored image
DNS Suffix , DNS Hostname , Workstation ID