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.