ref: 81327b0d993f9800423edbc086ec3e6b8e13d140
dir: /src/fix/rgbfix.1/
.\" .\" This file is part of RGBDS. .\" .\" Copyright (c) 2010-2021, Anthony J. Bentley and RGBDS contributors. .\" .\" SPDX-License-Identifier: MIT .\" .Dd March 28, 2021 .Dt RGBFIX 1 .Os .Sh NAME .Nm rgbfix .Nd Game Boy header utility and checksum fixer .Sh SYNOPSIS .Nm .Op Fl jsVv .Op Fl C | c .Op Fl f Ar fix_spec .Op Fl i Ar game_id .Op Fl k Ar licensee_str .Op Fl l Ar licensee_id .Op Fl m Ar mbc_type .Op Fl n Ar rom_version .Op Fl p Ar pad_value .Op Fl r Ar ram_size .Op Fl t Ar title_str .Op Ar .Sh DESCRIPTION The .Nm program changes headers of Game Boy ROM images, typically generated by .Xr rgblink 1 , though it will work with .Em any Game Boy ROM. It also performs other correctness operations, such as padding. .Nm only changes the fields for which it has values specified. Developers are advised to fill those fields with 0x00 bytes in their source code before running .Nm , and to have already populated whichever fields they don't specify using .Nm . .Pp Note that options can be abbreviated as long as the abbreviation is unambiguous: .Fl Fl color-o is .Fl Fl color-only , but .Fl Fl color is invalid because it could also be .Fl Fl color-compatible . Options later in the command line override those set earlier. Accepted options are as follows: .Bl -tag -width Ds .It Fl C , Fl Fl color-only Set the Game Boy Color\(enonly flag .Pq Ad 0x143 to 0xC0. This overrides .Fl c if it was set prior. .It Fl c , Fl Fl color-compatible Set the Game Boy Color\(encompatible flag: .Pq Ad 0x143 to 0x80. This overrides .Fl c if it was set prior. .It Fl f Ar fix_spec , Fl Fl fix-spec Ar fix_spec Fix certain header values that the Game Boy checks for correctness. Alternatively, intentionally trash these values by writing their binary inverse instead. .Ar fix_spec is a string containing any combination of the following characters: .Pp .Bl -tag -compact -width xx .It Cm l Fix the Nintendo logo .Pq Ad 0x104 Ns \(en Ns Ad 0x133 . .It Cm L Trash the Nintendo logo. .It Cm h Fix the header checksum .Pq Ad 0x14D . .It Cm H Trash the header checksum. .It Cm g Fix the global checksum .Pq Ad 0x14E Ns \(en Ns Ad 0x14F . .It Cm G Trash the global checksum. .El .It Fl i Ar game_id , Fl Fl game-id Ar game_id Set the game ID string .Pq Ad 0x13F Ns \(en Ns Ad 0x142 to a given string. If it's longer than 4 chars, it will be truncated, and a warning emitted. .It Fl j , Fl Fl non-japanese Set the non-Japanese region flag .Pq Ad 0x14A to 0x01. .It Fl k Ar licensee_str , Fl Fl new-licensee Ar licensee_str Set the new licensee string .Pq Ad 0x144 Ns \(en Ns Ad 0x145 to a given string. If it's longer than 2 chars, it will be truncated, and a warning emitted. .It Fl l Ar licensee_id , Fl Fl old-licensee Ar licensee_id Set the old licensee code .Pq Ad 0x14B to a given value from 0 to 0xFF. This value is deprecated and should be set to 0x33 in all new software. .It Fl m Ar mbc_type , Fl Fl mbc-type Ar mbc_type Set the MBC type .Pq Ad 0x147 to a given value from 0 to 0xFF. This value may also be an MBC name from the Pan Docs. .It Fl n Ar rom_version , Fl Fl rom-version Ar rom_version Set the ROM version .Pq Ad 0x14C to a given value from 0 to 0xFF. .It Fl p Ar pad_value , Fl Fl pad-value Ar pad_value Pad the ROM image to a valid size with a given pad value from 0 to 255 (0xFF). .Nm will automatically pick a size from 32 KiB, 64 KiB, 128 KiB, ..., 8192 KiB. The cartridge size byte .Pq Ad 0x148 will be changed to reflect this new size. The recommended padding value is 0xFF, to speed up writing the ROM to flash chips, and to avoid "nop slides" into VRAM. .It Fl r Ar ram_size , Fl Fl ram-size Ar ram_size Set the RAM size .Pq Ad 0x149 to a given value from 0 to 0xFF. .It Fl s , Fl Fl sgb-compatible Set the SGB flag .Pq Ad 0x146 to 0x03. This flag will be ignored by the SGB unless the old licensee code is 0x33! If this is given as well as .Fl l , but is not set to 0x33, a warning will be printed. .It Fl t Ar title , Fl Fl title Ar title Set the title string .Pq Ad 0x134 Ns \(en Ns Ad 0x143 to a given string. If the title is longer than the max length, it will be truncated, and a warning emitted. The max length is 11 characters if the game ID .Pq Fl i is specified, 15 characters if the CGB flag .Fl ( c or .Fl C ) is specified but the game ID is not, and 16 characters otherwise. .It Fl V , Fl Fl version Print the version of the program and exit. .It Fl v , Fl Fl validate Equivalent to .Fl f Cm lhg . .El .Sh EXAMPLES Most values in the ROM header do not matter to the actual console, and most are seldom useful anyway. The bare minimum requirements for a workable program are the header checksum, the Nintendo logo, and (if needed) the CGB/SGB flags. It is a good idea to pad the image to a valid size as well .Pq Do valid Dc meaning a power of 2, times 32 KiB . .Pp The following will make a plain, non-color Game Boy game without checking for a valid size: .Pp .D1 $ rgbfix -v foo.gb .Pp The following will make a SGB-enabled, color-enabled game with a title of .Dq foobar , and pad it to a valid size. .Pq The Game Boy itself does not use the title, but some emulators or ROM managers do. .Pp .D1 $ rgbfix -vcs -l 0x33 -p 255 -t foobar baz.gb .Pp The following will duplicate the header of the game .Dq Survival Kids , sans global checksum: .Pp .D1 $ rgbfix -cjsv -k A4 -l 0x33 -m 0x1B -p 0xFF -r 3 -t SURVIVALKIDAVKE \ SurvivalKids.gbc .Sh BUGS Please report bugs on .Lk https://github.com/gbdev/rgbds/issues GitHub . .Sh SEE ALSO .Xr rgbasm 1 , .Xr rgblink 1 , .Xr rgbds 7 .Sh HISTORY .Nm was originally released by Carsten S\(/orensen as a standalone program called gbfix, and was later packaged in RGBDS by Justin Lloyd. It is now maintained by a number of contributors at .Lk https://github.com/gbdev/rgbds .