Sega CD

Sega CD
Also known as: Mega-CD (JP), Sega Mega-CD (EU/AU) Developer: Sega Publishers: Sega, Tec Toy (BR) Released in JP: December 12, 1991 Released in US: October 15, 1992 Released in EU: April 19, 1993 Released in AU: March 1993 Released in BR: October 1993 This console has regional differences. This console has revisional differences.

The Sega CD was Sega's answer to the PC-Engine CD in Japan. It had fairly decent third-party support and a strong launch showing in Japan (where the Mega Drive was never in first place)... but between the Super Famicom's popularity in Japan, and Sega of America and Sega Europe's insistence on shoving out FMV games, that success just could not last anywhere. In fact, all those FMV games are what it's mostly remembered for now.

Version Differences

Variant Sega/Mega-CD systems include:

• Sega CD (US)/Mega-CD (Japan, Asia, Europe) [1991] - The original add-on model for separate Genesis/Mega Drive and Genesis 2 consoles.
• Wondermega (JP) [1992] - An all-in-one Mega Drive and Mega-CD, usually with other extra features. Both Sega and Victor marketed Wondermega models.
• Sega CD 2 (US)/Mega-CD 2 (Japan, Europe) [1993] - A cost-reduced add-on model for separate Genesis and Genesis 2 consoles, with a totally revised form factor.
• Sega PAC (Japan, US) [1993] - One of several add-on modules for Pioneer's LaserActive LaserDisc player (others include the NEC PAC for the PC Engine family). Allows the system to play not only Genesis and Sega CD games, but also the exclusive "LaserActive Mega LD" format: essentially, a LaserDisc with a similar game program to a Sega CD (these games constitute their own separate platform with a separate software library).
• Wondermega M2 (JP)/X'eye (US) [1993] - An all-in-one Genesis and Sega CD, usually with other extra features. A revised model of the original Wondermega, this time marketed just by Victor. The M2 version was the basis for the X'Eye, marketed in the US by Victor's parent company, JVC.
• CDX (US)/Multi-Mega (EU)/Linguaphone Education Gear (JP) [1994] - An all-in-one Genesis, Sega CD, and portable CD player.
• Aiwa CSD-GM1 (Japan) [1994] - A rare Aiwa portable stereo with a Mega Drive and Mega-CD integrated.

BIOS Versions

To do: See if any of these BIOSes will just load arbitrary code (not check the game region).

There are many, many, many different versions of the Sega CD BIOS, each featuring their own boot screens and UIs, and each running on a different set of Mega Drives.

Note: The Intro Type and UI Type numbering is arbitrary and provided for expository purposes only. They do not represent any sort of official classification or order.

System	Region	BIOS Ver.	Timestamp	Will the system run if connected to a Mega Drive that comes from...				Intro Type	UI Type
				...Japan?	...Asia?	...the US?	...Europe?
Mega-CD (model 1)	Japan	1.00g	11/20-1991 17:00	Yes	Yes	Yes	Yes	1	1
Mega-CD (model 1)	Japan	1.00l	12/02-1991 15:20	Yes	Yes	Yes	Yes	1	1
Mega-CD (model 1)	Japan	1.00o	12/06-1991 10:10	Yes	No	No	No	1	1
Mega-CD (model 1)	Japan	1.00p	12/17-1991 12:00	Yes	No	No	No	1	1
Mega-CD (model 1)	Japan	1.00S	12/28-1991 18:30	Yes	No	No	No	1	1
Mega-CD (model 1)	Asia	1.00S	12/28-1991 20:30	Yes	Yes	No	Yes	1	1
Sega CD (model 1)	US	1.00	08/04-1992 03:00	No	No	Yes	No	2	2
Sega CD (model 1)	US	1.10	10/11-1992 18:30	No	No	Yes	No	2	2
Mega-CD (model 1)	Europe	1.00	10/27-1992 15:15	No	No	No	Yes	3	1
Wondermega (Victor)	Japan	?	?	Yes	?	?	?	7-A	1
Wondermega (Sega)	Japan	1.00W	02/06-1992 01:30	Yes	No	No	No	7-A	1
Mega-CD 2	Japan	2.00c	12/22-1992 14:00	Yes	Yes	Yes	Yes	4	1
Sega CD 2	US	2.00	03/14-1993 01:00	No	No	Yes	No	5	3
Mega-CD 2	Europe	2.00	03/30-1993 12:00	No	No	No	Yes	6	3
Sega CD 2	US	2.00W	06/01-1993 20:00	No	No	Yes	No	5	3
Mega-CD 2	Europe	2.00W	06/01-1993 20:00	No	No	No	Yes	6	3
Sega CD 2	US	2.11X	06/21-1993 16:00	No	No	Yes	No	5	3
Sega PAC for LaserActive	Japan	0.98	03/29-1993 17:00	Yes	No	No	No	9	Inaccessible
Sega PAC for LaserActive	US	0.98	03/29-1993 17:00	No	No	Yes	No	9	Inaccessible
Sega PAC for LaserActive	US	1.04	09/22-1993 17:00	No	No	Yes	No	9	Inaccessible
Sega PAC for LaserActive	Japan	1.05	10/07-1993 11:00	Yes	No	No	No	9	Inaccessible
Wondermega M2	Japan	2.00	05/27-1993 13:20	Yes	No	No	No	7-B	4-A
X'Eye	US	2.00	12/27-1993 16:30	Yes	Yes	Yes	Yes	8	4-B
Aiwa CSD-GM1	Japan	2.11c	05/28-1993 14:00	Yes	Yes	No	No	4	1
CDX	US	2.21X	09/07-1993 19:00	No	No	Yes	No	5	3
Multi-Mega	Europe	2.21X	09/16-1993 14:00	No	No	No	Yes	6	3
Linguaphone Education Gear	Japan	?	?	Yes	No	No	No	6	3

(Source: GerbilSoft (region compatibility))

Intro Types

To do: Get higher quality videos of some of these.

Note: Different BIOS builds and/or different hardware may feature minor variations on what is otherwise the same intro type, such as changes to version numbering, copyright or labeling changes (e.g. Intro Types 7-A and 7-B).

Intro Type	Screenshot	BIOS Music	Notes
1		01	Typically used by: Japanese and Asian BIOS version 1.x on Mega-CD 1 systems Depicts the Japanese Mega-CD logo animated against a sky backdrop. A replica of this boot screen, complete with music, also appears as a gag in Panic! as scene 12-D. (Footage) The US localization of that game does not change the scene at all, even though no American Sega CD model features this boot screen.
2		02	Typically used by: US BIOS version 1.x on Sega CD 1 systems Depicts the Sega CD and SEGA logos animated against a space backdrop. Neither the first part of the animation, nor the first part of the background music, loop.
3		01	Typically used by: European BIOS version 1.x on Mega-CD 1 systems Depicts the European Mega-CD Logo and the SEGA logo animated against a space backdrop, similar (but not identical) to Intro Type 2.
4		01	Typically used by: Japanese BIOS version 2.x on, e.g., Mega-CD 2 systems Depicts the Japanese Mega-CD 2 logo (the only region with a Mega-CD 2 logo) and the SEGA logo, animated against a backdrop which features some geometric solids and Sonic striking one of his trademark poses. Among the animations are some that move the logos through the layer behind the shapes.
5		03	Typically used by: US BIOS version 2.x on, e.g. Sega CD 2 systems Depicts the Sega CD and SEGA logos animated against the same space backdrop from Intro Type 2. The animations are nearly (if not exactly) identical to those in Intro Type 4, but since the backdrop is different, they may look odd at times.
6		01	Typically used by: European BIOS version 2.x on, e.g. Mega-CD 2 systems Depicts the European Mega-CD logo and the SEGA logo animated against a similar backdrop to Type 4's, the biggest change being the replacement of Sonic with a yellow CD. Unlike Type 4, Type 6's animations keep the logos permanently layered on top of everything in the backdrop and no longer pass them behind the shapes. Otherwise, the animations are nearly (if not entirely) identical to the other versions.
7-A		01	Typically used by: Japanese BIOS version 1.x on Sega/Victor Wondermega systems The first of the Wondermega "Type 7" variants. Depicts a static Wondermega logo and an animated "W" logo against a spherical torus backdrop (from the Victor model's box art) whose colors cycle through the rainbow. The two Type 7 intros are identical except for their instruction captions and copyright information. In Type 7-A, they read as follows: Copyright Instruction ©SEGA 1991 Ver 1.00 スタートボタンを押して下さい (Press the Start Button)
7-B		01	Typically used by: Japanese BIOS version 2.x on Victor Wondermega M2 systems The second "Type 7" variant. identical to Type 7-A in every way, except for the instruction caption and copyright information having been revised as follows: Copyright Instruction ©VICTOR Co./SEGA 1993 Ver 2.00 ディスクチェック中 (Checking Disc) While the BIOS builds used by the Wondermega and Wondermega M2 both use very similar Type 7 variant boot screens, they use entirely different UIs from each other.
8		01	Typically used by: US BIOS version 2.x on X'Eye systems Another variant of Intro Type 7, virtually identical to the others apart from a) the obvious replacement of all the Wondermega branding with JVC and X'Eye branding, and b) the removal of a few animations. The X'Eye's BIOS otherwise shares its UI with the Wondermega M2.
9		N/A	Typically used by: Japanese and US BIOS version 0.98–1.x on the Sega PAC add-on for LaserActive The Sega PAC uses a barebones menu with Pioneer branding and copyright information. The screen has some animation: a large LaserActive logo zooming into the screen and stopping once it gets close, accompanied with a little descending whoosh sound. This screen is unresponsive in emulators or actual Mega/Sega CD systems, possibly due to differences between the respective hardware of the Sega PAC and conventional Mega-CD systems.

UI Types

Note: Different BIOS builds and/or different hardware may feature minor variations on what is otherwise the same UI type, such as minor design or labeling changes.

UI Type	Screenshot	Notes
1		Typically used by: Japanese, Asian and European BIOS version 1.x on Mega-CD 1 systems and Sega/Victor Wondermega systems; Japanese BIOS version 2.x on Mega-CD 2 systems
2		Typically used by: US BIOS version 1.x on Sega CD 1 systems
3		Typically used by: US and European BIOS version 2.x on Sega/Mega-CD 2 systems
4-A		Typically used by: Japanese BIOS version 2.x on Victor Wondermega M2 systems
4-B		Typically used by: US BIOS version 2.x on JVC X'Eye systems A slight variant of UI Type 4-A, which drops both the Pitch button and the "MUSIC" caption along the top of the interfae.

Region Lockout

Some Sega CD Boot ROMs have checks in place to prevent you from mixing and matching different region Sega CDs and Geneses (Genesi?). If the Boot ROM with region locking detects a region mismatch at boot, then it will display a message in black text on a light blue background. This message changes depending on which region of Sega CD you have.

Japan	US	Europe

Interestingly enough some Boot ROMs that don't region lock consoles (such as the JVC X'Eye's Boot ROM) have the message for the lock out still inside the ROM viewable through a hex editor.
Early Boot ROMs such as 1.00g seem to be the exception

Option/Memory menu

To do: See if other BIOSes (CDX and Aiwa) have different icons for the save manager screen. Rip the Icons from the ROM for better viewing (This might be hard, because the Icons seem to be compressed in the ROM somewhere)

Boot ROMs intended for different models of Sega CD hardware, appropriately enough, change the icon of the console in the save data management menu to match their model.

The X'eye and WonderMega M2 use a different color palette for this screen causing the ram cartridge icon to look a little darker

Japanese boot ROMs

Wondermega	Wondermega M2

US/European boot ROMs

Model 1	Model 2	X'eye

The X'eye uses a different font compared to the Sega CD model 1 and 2.