ROM Header: Difference between revisions
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{| class="wikitable"
!Offset
!Size
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All known commercial games use
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Cruis'n USA sets this field to
|-
|0x08
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|Revision version of libultra, as ASCII letter.
|}
For instance, libultra version "2.0L" is reported as
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|0x10
|0x8
|Check Code
|64-bit check code calculated on 1 Mbyte of ROM contents starting from offset 0x1000 (after IPL3). This check code is computed with a custom algorithm implemented by IPL3 that verifies the integrity of the ROM before booting it. If the check code doesn't match, IPL3 refuses to boot the ROM and hangs the console.
Sometimes, these 8 bytes are referred to as "CRC HI
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For the Conker's Bad Fur Day debug ROM, this field is set to <code>6F 23 01 3A 2F C9 CB 36</code>. For the Perfect Dark debug ROM, this field is set to <code>54 E4 D8 38 2F BD 95 36</code>. Since both of these games were made by RAREWARE, this field could be a check code for their Security Dongle hardware, which was required to be able to boot these games on the N64.
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|0x3B
|0x4
|Game Code
|The game code is 4 ASCII characters that are split up into 3 parts - the category code, the unique code and the destination code.
{| class="wikitable"
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|0x0
|0x1
|Category Code
|An alphanumeric character that specifies the kind of media the game is stored on.
{| class="wikitable"
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|-
!D
|64DD Disk
|-
!C
|Expandable Game: Game Pak Part
|-
!E
|Expandable Game: 64DD Disk Part
|-
!Z
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|0x1
|0x2
|Unique Code
|Two alphanumeric characters that identify the game.
|-
|0x3
|0x1
|Destination Code
|An alphanumeric character that specifies the destination the game is intended for.
{| class="wikitable"
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|0xFC0
|IPL3
|This area contains the [[IPL3|IPL3 boot code]]. Each ROM ships its own IPL3 that is meant to work together with the [[CIC]] installed in the ROM. Before running IPL3, IPL2 checks its checksum also using a seed coming from the CIC, which binds each IPL3 code to a specific version of CIC.
|}
==
The Advanced Homebrew ROM Header format is a convention that has been agreed upon in the N64 homebrew community to add additional information in the header, using unused fields. The goal of this convention is to let homebrew ROMs declare the correct saveype and controllers that are expected to play the game. The format has been introduced by the EverDrive 64 flashcard and has been later enhanced by the homebrew community.
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Instead, by using the Advanced Hombrew ROM Header, emulators can automatically configure the required emulated hardware as expected without having to keep any additional database, by simply decoding specific fields of the ROM header. In addition to emulators, also development flashcarts and loaders can use this format to automatically configure the correct savetype when the ROM is loaded.
===
{| class="wikitable"
!Offset
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|1
|Controller 1
| This byte contains the suggested / expected controller hardware that should be attached to port 1.
Values 0x01-0x7F indicate a standard N64 controller, possibly with some installed pak.
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|N64 controller with Controller Pak
!0x82
|Gamecube controller
|-
!0x03
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|-
!0xFF
|Nothing attached to this port
!0x84
|Gamecube keyboard
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|1
|Controller 2
| This byte contains the suggested / expected controller hardware that should be attached to port 2. See byte 0x34 for more information.
|-
|0x36
|1
|Controller 3
| This byte contains the suggested / expected controller hardware that should be attached to port 3. See byte 0x34 for more information.
|-
|0x37
|1
|Controller 4
| This byte contains the suggested / expected controller hardware that should be attached to port 4. See byte 0x34 for more information.
|-
|0x3C
|2
|Game ID
|This must contain the ASCII characters "ED". It is used as an ID to identify that the Advanced Homebrew ROM header format Is being used by this ROM.
|-
|0x3F
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|}
===
Emulators not listed here do not support the advanced homebrew ROM header format.
{| class="wikitable"
|+
!Emulator
!Current support
|-
|Ares
|Supports Savetype only
|-
|cen64
|Supports Savetype only
|}
===
Support by flashcarts can vary depending on the USB loader being used and/or the flashcart operating system. Notice that flashcarts can emulate a specific savetype but have nothing to do with controllers, so the maximum expected support is related to savetype.
{| class="wikitable"
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|-
| rowspan="4" |64drive
|64drive official C tool
|None
|-
|64drive menu
|None
|-
| |||