New Custom Dreamcast BIOS v1.032 Relased

RaZiel · Jun 22, 2016

http://japanese-cake.livejournal.com/10056.html

It is here and didn't seem to go noticed but I wanted to share as I donated to this as it is so amazing. THought you all might enjoy as well.

_________________________________________________________________________________________

Dreamcast Custom bootROM v1.032
by japanese_cake 20/06/2016
_________________________________________________________________________________________

[+] What is that?
~~~~~~~~~~~~~

It is a modified BIOS for the SEGA Dreamcast. It is based on the retail BIOS v1.01d.
It can be used either in emulators or in a real Dreamcast console. Each version is
released with two types of boot animation: retail and devkit.

[+] What does it do?
~~~~~~~~~~~~~~~~

This version has the following features:

Region free:
Boot GD-ROM/MIL-CD from any region. The J/U/E flags as well as the area
protection slots that reside in the IP.BIN are now simply ignored.

Auto region patching (only for GD-ROMs):
To enhance game compatibility and by-pass region protection, the bootROM
changes the system region to the one of the game. For instance if you launch the US
version of "Silver" on a PAL system, assuming the J/U/E flags check is skipped, the
latter crashes deliberately. With this BIOS the system region is overwritten with the
one of the game right before passing the control to the game. Therefore, it boots
correctly. Examples of games that perform a region check:
- Urban Chaos v1.001 (2000)(EIDOS)(PAL)(en-fr)[!] (T36810D 50)
- Urban Chaos v1.000 (2000)(EIDOS)(NTSC)(US)(en-fr)[!] (T36810N)
- Silver v1.000 (2000)(Infogrames)(PAL)(M3)[!] (T15109D)
- Silver v1.001 (2000)(Infogrames)(PAL)(en-nl)[!] (T15109D)
- Silver v1.001 (2000)(Infogrames)(NTSC)(US)[!] (T15108N)
- San Francisco RUSH 2049 v1.002 (2000)(Midway)(PAL)(M6)[!] (T-9709D-50)
- San Francisco RUSH 2049 v1.001 (2000)(Midway)(NTSC)(US)[!] (T-9707N)
- Elemental Gimmick Gear v1.001 (1999)(Vatical)(NTSC)(US)[!] (T41601N)

Some other games do an additional check: the video broadcast. A game such as
"San Francisco RUSH 2049" checks whether the system video broadcast is "correct": the
NTSC/US and PAL/EURO version expect the video broadcast to be set to NTSC and PAL,
respectively. An easy way to by-pass the broadcast check consists in overwriting the
system video broadcast by the one normally used in the game region. The only drawback
in doing so is that people that have a region-mod will see the video broadcast they
have set overwritten. Therefore, the video broadcast patching is done on a per game
basis. So far I have identified 3 games that do such check:
- Elemental Gimmick Gear v1.001 (1999)(Vatical)(NTSC)(US)[!] (T41601N)
- San Francisco RUSH 2049 v1.001 (2000)(Midway)(NTSC)(US)[!] (T-9707N)
- San Francisco RUSH 2049 v1.002 (2000)(Midway)(PAL)(M6)[!] (T-9709D-50)

If you think there are other games that do a video broadcast check, please
contact me, I would then update the BIOS accordingly.

Note that the auto region patching is enabled only with GDROMs and GDI images. I
assume that backups do not need it as they have already been cracked.

Forced video mode to NTSC/PAL-60Hz:
The bootROM animation, menu and license screen now use a video mode forced to
60Hz. On PAL system with the R422 mod or NTSC US/JAP system, the output signal
should be NTSC (60Hz), otherwise the output signal is PAL, with a 60Hz refresh rate.

Now some PAL games (not all of them sorry!) like for instance House of the Dead 2
run at 60Hz! Games that have their video mode hard-coded are not affected though.

I do not really know whether forcing the video mode to 60Hz can cause problems
for some people. If so please contact me and explain why. Thank you!

No VGA flag check:
Whether or not the game supports the VGA output, it boots. There are games that
support the VGA cable but for some reason the VGA flag in the IP.BIN is not set. The
use of a boot CD was thus needed. Now, you will never get the annoying "This game
doesn't support the AV cable [...]" anymore.

No bootfile LBA check:
Allow a game to boot even if its bootfile, more commonly called 1ST_READ.BIN, is
not located on the outer part of the disc. I don't know whether it can be of any use
for people using discs. However, for the lucky owners of ODDE for Dreamcast, you can
re-build games' track 3 without any padding.

For instance, with "Dreamkey 3.0 v1.001 (2001)(Sega)(PAL)(M8)[!]", the track03 is
~1.10GB. Re-building the track (track03.iso) using the following command:
mkisofs -C 0,45000 -V DREAMKEY3 -G IP.BIN -l -o track03.iso data
will made the track03.iso way smaller (only ~93MB). Homebrews can also be
rebuilt to GDI so that the 0GDTEXT.PVR texture shows up in the audio player

Display bootROM version:
The current version of the bootROM appears in the up-right corner of the screen
so that you know what BIOS is running.

Date/Time screen skip:
Everytime the system boots up, it checks whether the real time clock (RTC) is
set. If it is not, you are then asked to set the date and time. The datetime value is
then kept up to date by a small integrated circuit which uses an alternate power
supply: usually a rechargeable Sanyo ML2430 battery.

Back in the days when you got your brand new Dreamcast from a retailer, you had
to set the date once then you were good until you power off the console for more than
a couple of weeks or so. But with age, that battery gets a bit lazy and does not keep
the charge anymore. Everytime you shutdown your Dreamcast, the datetime value is lost
and everytime you switch it on you have to set that value again. One way to fix this
consists in changing the battery by a new one.

But, as the date and time are not required to play and I am sure you do not turn
on your Dreamcast to know what time it is, we can fix that problem via the software.
The custom bootROM sets a default date and time value so you do not get the
"set date/time" screen anymore (see note #1).

No VMU copy-protected file check:
Some games do not allow you to copy their saves to other VMUs. Pretty annoying,
right? Well, now you are free to do whatever you want (see note #2).

Fade-in and fade-out colors:
Depending on the boot settings (SEGA license screen and direct-boot) and the type
of media inserted (GD-ROM or MIL-CD), the custom bootROM changes the fade-out and the
fade-in colors when entering and exiting the Dreamcast main menu.

For example, when launching a MIL-CD or a backup, a black fade-in color is used
to exit the main menu. However, if the direct-boot option is on, the color used will
either be black or white depending on whether the SEGA license screen is skipped or
not. This make the player's visual experience similar between booting a GD-ROM or a
MIL-CD/backup.

Custom bootROM settings:
The custom bootROM provides new options to change boot behaviors and to customize
the interface. You can change those options directly from the Dreamcast settings menu
by pressing the "START" button. A window appears and prompts you select the settings
you want to change. Read the next section to know more about those new options.

[+] Details about the custom bootROM settings
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Starting from this version, v1.032, the custom bootROM handles new settings that
can be changed from the Dreamcast settings menu by pressing the "START" button. Those
settings are stored in the same way as original settings (language, date, audio and
auto-start) in the Dreamcast internal flash memory. Note that the original and custom
settings are saved only when you exit the Dreamcast settings menu.

Boot animation (default: system region):
Select the color of the boot animation swirl (color based on the system region,
blue, orange or black). You also have an option to skip the boot animation
(see note #3). Currently, the interface to pick up a custom color other than the ones
suggested does not exist. This feature will be available in future versions of the
custom bootROM.

SEGA License screen skip (default: off):
Decide whether the Dreamcast displays the SEGA license screen. In any case, the
IP.BIN initialisation and bootstraps code is still executed to be compatible with
homebrews that rely on a specific machine state at this point of execution.

MIL-CD/backup direct boot (default: off):
Decide whether the system resets when launching a MIL-CD/backup (see note #4).

Dreamcast main menu (default: 2D perspective):
Select the perspective and scenery color of the Dreamcast main menu. This feature
is based on the Puyo Puyo Fever easter-egg that changes the Dreamcast main menu
perspective from 2D to 3D. Here slightly more options are presented. You can keep the
2D perspective and choose between a light-grey or dark-blue scenery color or switch
to the 3D mode, that some people use to call the "3D menu hack" (that is rather a
hidden feature than a hack). Note that with the 3D perspective, the analog stick and
the triggers are used the mode the camera.

[+] Notes and limitations
~~~~~~~~~~~~~~~~~~~~~

Note #1:
If the date/time is not set, the custom bootROM set it for you. In the case a
GD-ROM disc is inserted, the latter boots right away. However, by design in the
original bootROM, if it is a MIL-CD/backup disc, you enter in the Dreamcast main menu
therefore have to manually launch the game. This may be fixed in future versions.

Note #2:
Once a protected save has been copied, when you browse your saves via a no-custom
BIOS, you will notice that the original save file cannot be copied whereas its copy
can. In fact, the copy-protected flag is not stored in the save file itself but
rather in the VMU filesystem. That means that the custom bootROM updates and clears
that flag only when the save is copied to another VMU.

Note #3:
The "No boot animation" option works perfectly when using a GD-ROM drive. However
it may not boot MIL-CD/backup directly if you use ODDEs. I believe the creators of
ODDEs would be able to easily fix this by issuing a new firmware if necessary.

Note #4:
Once the system has detected a GD-ROM, it locks the drive in such way that only
GD-ROMs can be launched afterwards, unless the system resets. The only reason why you
would disable the direct boot feature is if you want to boot a MIL-CD or a backup
after booting a GD-ROM with a GD-ROM drive. Some users have reported this feature
not working when using USB GD-ROM. As it is working with any GD-ROM drive and GD-EMU,
I believe the problem is in USB GD-ROM firmware.

[+] Does it work on the real hardware?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Yes, sure, as long as the Dreamcast has a BIOS mod and Dreamshell to flash the
alternate BIOS chip.

[+] Note about the Holly integrity check
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Those of you that have tried to modify a Dreamcast BIOS probably know that you
can only get it working on real hardware if the BIOS passes the integrity check done
by the Holly controller. A retail BIOS uses its 2Mb of data to pass this check. So
every time you modify something, unless you know the algorithm running in the Holly
controller, you must flash your Dreamcast and see if it works. If it doesn't, you
have then to modify some data in the BIOS, flash your Dreamcast again and pray that
this time your BIOS passes the check.

Sometime ago, MetalliC made an important discovery: he found a NAOMI beta BIOS
that uses only 1Kb of data to pass the integrity check. This 1kb of data that
we call "beta bootstrap" can be injected inside a retail Dreamcast BIOS. By doing so,
the BIOS passes the check and you can then modify whatever you want in the BIOS,
except the beta bootstrap of course. MetalliC implemented this mechanism in a BIOS
shipped with DreamShell.

So then what? Well, even though this beta bootstrap by-passes the integrity check
it however does not handle the system reset that is triggered every time you boot a
MIL-CD/backup. What a pain! This is where my work comes in. With a little of luck, my
empirical analysis of the integrity check lead me to interesting findings: I found
a way to modify the beta bootstrap so that it not only passes the integrity check but
also handles the system reset correctly. I am not giving more details here as people
interested in the technical aspects will, without a doubt, be able to understand by
themselves by looking at my BIOS.

[+] Does it work with GD-EMU and USB-GDROM?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As I do not own a USB-GDROM myself, I cannot test the compatibility. However I
do test the custom bootROM with both a real GD-ROM drive and a GD-EMU. Other than the
limitations explained before (see "Notes and limitations"), the custom bootROM is
fully compatible with GD-ROM drive and GD-EMU.

[+] Is it compatible with all games?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With the custom bootROM, I try to improve the compatibility with retail games and
to add new features. Unfortunately, the changes I made in the bootROM break the
compatibility with some independent games. In order to protect themselves against
piracy, they use anti-protection mechanisms that rely on specific data that is
slightly different in this custom bootROM.

Here is a non-exhaustive list of titles that are not compatible with this custom
bootROM:
- Bleemcast! (the 3 of them)
- Cheat discs such as Action Replay, Game Shark and Code Breaker
- Pier Solar

However, I plan to hack and release at least one of those cheat discs compatible
with this BIOS.

[+] Why using "1.03X" as the version number?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The v1.004, v1.011, v1.01c, v1.01d and v1.022 are the only version numbers known
for the official SEGA bootROM (BIOS). Thus I decided that my custom versions will use
version numbers starting from v1.030.

[+] Greetings and special thanks to:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

- Lars Olsson for his work reverse-engineering the Dreamcast bootROM
- Link83 for his devkit boot animation hack
- DC-SWAT team for their DreamShell OS
- drkIIRaziel and ZeZu for their nullDC emulator
- Deunan for his great GDEmu board
- neuroacid for his cool app, GDMenu, and his work to make it compatible with
this bootROM
- MetalliC who discovered and dumped the beta bootstrap that now makes my work
way easier!

And of course to people who donated and have been supporting my project.

Thank you to all of you!

_________________________________________________________________________________________

jc.dcdev@gmail.com
japanese-cake.livejournal.com
_________________________________________________________________________________________
Click to expand...

skyway1985 · Jun 22, 2016

Impressive! when i finish my bios install in my Va0 im def gonna test this out!

MeteK · Jun 22, 2016

Tested with my gdemu console, blackscreen after launching a game.

-=FamilyGuy=- · Jun 22, 2016

MeteK said: ↑

Tested with my gdemu console, blackscreen after launching a game.
Click to expand...

Yeah... You clearly didn't read the readme did you?

That said, when he adds support for cheatdiscs/gdmenu, it'll be the perfect bios!

MetalliC · Jun 22, 2016

readme says it not compatible with cheatdisks and bleem! only, but I suspect none of pirate/homebrew Mil-CDs will work at all.
anyone was able to boot some CDs with that biosmods ?

RaZiel · Jun 22, 2016

I will give it a go once I am home if no one report's back. I also have a few official Mil-CD's I will test out. Also want to try Ghost Blade and Sturmwind since Pier Solar was reported as not working.

madsheep · Jun 22, 2016

- neuroacid for his cool app, GDMenu, and his work to make it compatible with
this bootROM
Click to expand...

so we need this special version

japanese_cake · Jun 23, 2016

MetalliC said: ↑

readme says it not compatible with cheatdisks and bleem! only, but I suspect none of pirate/homebrew Mil-CDs will work at all.
anyone was able to boot some CDs with that biosmods ?
Click to expand...

I promise that, unless I made some of my last minute changes that broke the compatibility, it works (don't know about real milcd though as I don't own one). After the bootROM unscrambles the main binary, as you mentioned, it sets the register 0xa05f74e4 with 0x42fe. If you skip this, the drive remains unlock. But, as all apps/games (not talking about genuine mil-cd, only backups here) expect the drive to be locked, they call the gdcInitSystem syscall then do the ROM copy (with the 2Mb) to unlock the drive, which of course does not work in our case because the 2Mb do not pass the check anymore. What this bios does is that it hooks this syscall, unlocks the drive with the proper data (beta bootstrap) then gives the control back to the game. The reason why you may think it does not work is probably because it has been stated that once the holly check has failed, the drive cannot be unlock useless you reset the system. However, during my testing, I have found that not to be true. (Maybe because the drive has been unlock correctly at least once since the system started?)
Anyway, give it a try and let me know about your findings.

japanese_cake · Jun 23, 2016

RaZiel said: ↑

I will give it a go once I am home if no one report's back. I also have a few official Mil-CD's I will test out. Also want to try Ghost Blade and Sturmwind since Pier Solar was reported as not working.
Click to expand...

This is good that you have genuine milcd. Btw did someone dump those milcd? I would be interested in having a look.
I don't own the two games you mentioned but I am pretty sure that if they have some kind of a copy protection, they won't work. Anyway, I'm interested in your feedback Thanks

MeteK · Jun 23, 2016

So why do i get a blackscreen when launching a game with gdemu with the "No boot animation" option off ?

MetalliC · Jun 23, 2016

japanese_cake said: ↑

Btw did someone dump those milcd? I would be interested in having a look.
Click to expand...

not sure about all 8, but most of them is dumped, you can get them at Trurip romset

RaZiel · Jun 23, 2016

MetalliC said: ↑

not sure about all 8, but most of them is dumped, you can get them at Trurip romset
Click to expand...

I am the guy that added them to Trurip. The CDI images were obtained from UG years ago but the Space Channel 5 Mexican Flyer image in CCD format was dumped with Trurip from my pressed disc and it is a perfect 1:1 image. It is however region locked to JP but I'll let you know once I get a little time. Been working double shifts here lately with little time.

skyway1985 · Jun 23, 2016

im going to finish my bios install tonight just to test this bios!!! thanks for the hard work!

RaZiel · Jun 23, 2016

MeteK said: ↑

So why do i get a blackscreen when launching a game with gdemu with the "No boot animation" option off ?
Click to expand...

Check the readme bud. GDEMU is not supported till the dev adds support.

MeteK · Jun 23, 2016

Ok, i'll wait for Deunan's new FW then

takeshi385 · Jun 23, 2016

I love these bios.

Flappyraccoon · Jun 24, 2016

RaZiel said: ↑

Check the readme bud. GDEMU is not supported till the dev adds support.
Click to expand...

GDEMU works fine with this bios it's GDMenu that doesn't work. I flashed my bios to 1.032 just out of morbid curiosity and launching from GDMenu gave black screens. You can just boot the Dreamcast with the sd removed then switch to Dreamshell and flash back to 1.031 until the fixed versions are released. That's what I did anyway. Great progress on the bios by the way!

MeteK · Jun 24, 2016

It's exactly what i was thinking that gdmenu doesn't seems to work.

I rolled back to 1.031 too.

takeshi385 · Jun 24, 2016

I can't wait for the option for a custom swirl color to be added, I have always wanted a purple swirl.
Edit: dreamshell won't work on the new bios.

TerdFerguson · Jun 25, 2016

Very nice, I've been following this project for awhile. I'm really glad to see the option for blue swirl. I'm going to do the mod just for that, but I may wait for another update or two since once I do the bios install I'm not doing it again lol

@japanese_cake where do I eventually donate?

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New Custom Dreamcast BIOS v1.032 Relased

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