Super Game Boy 2: Boot Into Games on the First Frame

The Super Game Boy is a game accessory that plays original monochrome Game Boy games as well as black Game Boy Color games using the SNES console as an input interface with audio and video output display to the TV. The focal point was allowing players finally being able to play Game Boy games on a more accessible bigger screen, as well as having the ability to assign all 4 of the monochrome palettes to a 15-BIT value.

Games could also be developed to take advantage of the additional functions of the SNES, though they were almost completely wasted in games. Most developers just opted to throw up a border and palettes that were often incomplete and weren’t very good, as well as often locking out the player from changing palettes and or controller settings. Games could allow up to 4 players to play limited modes by plugging in a SNES Multitap accessory allowing Bomberman deathmatches, Street Fighter 2 tournaments and even the more obscure turn-based board games would be setup to work without passing a single controller to other players.

A small number of games offered alternate soundtracks using the SGB sound driver, games even uploaded their custom own sound samples and that was much less common. Only one game, Space Invaders actually uploaded an early version of the game running in the SGB’s RAM. The ability to write custom hooks in both RAM and ROM were also possible though never actually used in any meaningful way.

The Super Game Boy / 2 boots into games after 29 frames. Instead of booting instantly into the game, the SGB will load an uncontrollable black screen with audio playing. This cuts off the intro frames of games. It may have been an arbitrary design choice, depending on how you see things from a technical standpoint. It is unknown why Nintendo made this decision, but it may have been done to prevent "garbage" from displaying on-screen in certain games.

Changes were made with the SGB2 revision causing graphics to be less glitchy, and appears related to the stack read changing from FE to FF in the bootrom used detect between SGB and SGB2 and can cause certain games to behave differentl when booting the first few frames. The first two screenshots show kirby's Dream Land boot sequences on the exact frame with both SGB and SGB2.

Pac-Man is the reverse situation where it is only affected by the SGB2. The first few display garbage frames. Kaeru no Tame ni Kane wa Naru, the Japanese exclusive displays garbage before updating the LCD status to display text with both the SGB and SGB2. There are most likely other game examples.

Included are patches for all known Super Game Boy / 2 regions and revisions because addresses are slightly offset between versions.

Known issues and or limitations
-Screen garbage may appear at the first few frames depending on what game is played. Some may consider this an issue or limitation, but it is actually how the games were originally designed and may be more or less obvious with original DMG, Game Boy Pocket and Game Boy Color models.

The Super Game Boy / 2 boots into games after 29 frames. Instead of booting instantly into the game, the SGB will first load an uncontrollable black screen with audio playing. This cuts off the intro frames of games. It may have been an arbitrary design choice, depending on how you see things from a technical standpoint. It is unknown why Nintendo made this decision, but it may have been done to prevent "garbage" from displaying on-screen in certain games.

Changes were made with the SGB2 revision causing graphics to be less glitchy, and appears related to the stack read changing from FE to FF in the bootrom used detect between SGB and SGB2 and can cause certain games to behave differentl when booting the first few frames. The first two screenshots show kirby's Dream Land boot sequences on the exact frame with both SGB and SGB2.

Pac-Man is the reverse situation where it is only affected by the SGB2. The first few display garbage frames. Kaeru no Tame ni Kane wa Naru, the Japanese exclusive displays garbage before updating the LCD status to display text with both the SGB and SGB2. There are most likely other game examples.

Included are patches for all known Super Game Boy / 2 regions and revisions because addresses are slightly offset between versions.

Known issues and or limitations
-Screen garbage may appear at the first few frames depending on what game is played. Some may consider this an issue or limitation, but it is actually how the games were originally designed and may be more or less obvious with original DMG, Game Boy Pocket and Game Boy Color models.

Database match: Super Game Boy 2 (Japan)
Database: No-Intro: Super Nintendo Entertainment System (v. 20210222-050638)
File/ROM SHA-1: E5B2922CA137051059E4269B236D07A22C07BC84
File/ROM CRC32: CB176E45