Release: Custom BootROM v1.032

Hi there,

A couple of months ago, I thought I was ready to release my new bios. Unfortunately for me, at that time, I was really busy and my bios mod started to show weaknesses. As I don't have the right soldering equipment, I had to work with my Dreamcast and all its little faulty contacts. I worked hard to get the reset exception working correctly... actually way more than I should have! The reason? On my Dreamcast, the faulty contacts I mentioned were crashing the Dreamcast upon reset! I took me quite some time to figure this out :/

That was quite unfortunate for me but at least it gave me the opportunity to have a glance at other things. I explored a bit how the region protections games like San Franciso RUSH 2049 have and came up with a solution that fake the system region. Later I decided to force the video signal to output a 60hz refresh rate (more details in the readme file) and so on and so forth. So now the bios I'm releasing today is way more advance than I planned initially.

With the holidays coming, I don't want to hold it any longer. However I prefer to warn you beforehand: even if I tested most of the features, I can not guarantee that everything is 100% working (and constructive feedback is welcome). I am sorry for this but no worries, the bios does not contain some kind of bad-ass code that could destroy your Dreamcast ;)

I tried my best to add new features, improve compatibility with some naughty retail games. But it comes with some drawbacks: no cheat disc until I release one compatible with my bios, some independent games like Pier Solar do not work anymore (again, more details in the readme file). I will address those problems later. For those using GD-Emu, you are probably also using the GD-Menu app Neuroacid created. Well here again it doesn't work anymore, but soon a compatible will come to light! By the way, kudos to neuroacid who saved me time and helped me a lot for the testing!

Ok, that's enough talking for now, let's check the features out:

bootROM v1.032 Retail & DevKit Changelog:

  • In BIOS menu to update the following bootROM settings (Boot animation color, SEGA license screen skip, MIL-CD/backup direct-boot, Dreamcast main menu scenery perspective and color)

  • Skip the "set date/time" screen

  • BIOS video mode forced to 60hz

  • Auto region patching for GD-ROMs

  • Internal changes for future updates

Please read the readme file to see the complete list of features.

Download link (contains retail & devkit boot anim):

  • jc-bootROM-retail-v1.032.bin SHA1: ec42875983f33cefafe8616eb9152cf0172136ae

  • jc-bootROM-devkit-v1.032.bin SHA1: b5b00b3a34d6556abb34450d0fb9d37a57d7dd05

See you soon!

Beta bootstrap + reset: Mission complete

I feel like some people like to claim that it is impossible when they fail to overcome problems. Fortunately, their vision has a limited influence. If I listened to all the negative comments about my projects, I would probably end up being like their authors, spreading my frustration over the Internet.

Anyway, that is not the point I want to talk about. Today, I am happy to report my progress. Let's start with the bad news. In its current state, my next bios version cannot boot cheat discs like Action Replay/Gameshark/Code breaker and GDMenu. I know why and there are solutions to this. The good point is even though some people state that it is not possible, the beta-bootstrap I slightly modified works flawlessly with MIL-CD/backup, including the system reset. I can even add that I knew it would pass the holly protection before testing it on the real hardware. Pretty cool isn't it? But to be honest, my moves are limited but I hope that in a near future I will be more free.

In short, I could release my bios right now, and release the "patched" cheat disc later. But I am not sure yet that this would be the best solution to introduce the custom cheat-disc for my bios, specially as there is a chance that I will overcome this issue. Booting custom bios is already a difficult task for users and I don't want to bother them with a "special version" of games/applications. Anyway, whatever solution I come up with, the compatibility is not going to be impacted.

Stay tuned!

GDROM-Explorer: better late than never

Hi there,

Pending the next BIOS release, I decided to update GDROM-Explorer. I received feedback some several people saying that some files were corrupted after extraction. Well that was a really silly bug, a piece of code I forgot about when I was doing some code refactoring a while ago :( Thanks to tormod who saved me a lot of time comparing files, I could easily nail down the problem. I am sorry for those who wasted time on this. The good news is that, even I took me more than a year to update my program, you finally have now a fixed version!!!


I have also been asked to add a new feature, a new file format to support (Thanks again tormod). This will come in another release (v1.7) planned for later this year.

Enjoy and see you soon!

The wait is almost over!

Hi everyone,

A couple of weeks ago, I was feeling comfortable enough to release my next custom bios before 2016. Then I postponed the release date to February. Right now I cannot commit on a release before March. I am sorry about this but you have to understand that it is also frustrated for me! I have been working hard in the next version despite a busy schedule and substantial personal changes.

The good point is that the version 1.032 is "feature complete" and is working properly. I introduced new features and cool customization options. I have only one thing that stops me from releasing my custom bios: the holly check.

As you may know, at boot time the bios is copied from the chip to the RAM and the Holly controler performs some sort of a checksum to determine whether the bios is legit or not. If it is not, the GD-ROM drive is locked and ypu cannot play any game. So far I have been using code (bootstrap) from a beta naomi bios (a beta version The House of the dead 2) in which only a small part of the bios is checked, leaving the rest up for modifications (Thank dknute for the intel and MetalliC for the first implementation!) That is the way I validate my code on real hardware. Then I inject my patches in the retail bios and more or less bruteforce the Holly check. Right now I have to make the bios pass this check, this is the final step. You may ask "why not releasing the bios with the beta bootstrap?". Well, here is the heck: this "beta" bios does not support the manual reset (read soft-reset) so you are not able to boot milcd and play with boot discs. I patched the beta bootstrap to handle the sof-reset but as It modifies to the data used by the Holly controller to unlock the drive (more precisely the G1 bus) I face the same issue again: the modified beta code has to be altered to pass the Holly validation. So here I am, trying to get lucky! It takes some times (that I will have next week) but I feel confident. I know that it is not because you change kb of data that this step is harder. I was already able to pass the check with a bios that had more 32kb of data different from the original bios. If by chance I can make the beta bootstrap code with the reset pass the Holly check, I will not have to bruteforce any other custom bios. It is definitely worth trying!

In brief, cross your fingers and wait!

The legend will never die


Our favorite console is definitely not dead and not even dying! Every year I am so surprised to see how many games, mods, prototypes, tools and accessories get released. I really like that system. I do not own any of the last generation consoles and I think it is better that way. I am so furstrated to see that when you buy a game for new systems, the first thing you have to do is to download a small 1 or 2 GB update, because of course the game is still in a sort of non-official "beta" version. So you basically pay video-game editors to help them debug their games... Well I prefer to live in the past, where games were made by passionate people, carrying values other than profitability.

With Christmas coming, I really wanted to release a new version of my custom BIOS but there is a lot happening in both my personal and professional life. Even if I may have differently, I am not going to release the BIOS before January. First, I have technical issues: my modded Dreamcast seems to have a loose electrical connections somewhere and I do not have an iron at my place to fix this. Second, there is something that is not working correctly with my new BIOS and this problem cannot be neglected. Finally, the release is made up of two elements: the BIOS itself and its configuration tool for the customization and I am late in the development of the latter.

Pending the next release, I have created a youtube playlist with two new videos. I hope you will like them.

Also I would like to thank the people who donated. I will probably spend that money on a new iron ^^ Thank you!!!

Merry Christmas everybody,

See you in January!

Blood censor activated!

Hello everyone,

Quick update regarding the next custom bios. I have been working a lot on this version (v1.032) but unfortunately, the most important changes will be barely noticeable for most players. At least, starting from the next version, it is going to be easier for me to make progress and offer what people have always been waiting for. Aside from the next version, I have also worked a bit on the customization: changing the swirl and background color is definitely possible. I don't know whether I can release that now though.

I would also like to emphasize that I have spent quite a huge number of hours on this project and even if I am a big Dreamcast fan, I still am a human that needs motivation/support. I contribute to some other projects or platforms, money or time wise, so I would really appreciate if you could the same, as a compensation for my work. By doing so, whatever the amount of money you give, you then join the others ide of the scene, where you can legitimately claim that cool stuff happens not only thanks to me but also thanks to you ;)

Custom BIOS goes to version 1.031!

Hi there,

I have been working quite a long time on that version. And not necessarily on the features that may sound hard. Changing from white to black the fade-in color when booting a GD-ROM took me a couple of hours. I was looking for something that does not exist in the code so that kinda explains why :) That version is intermediate in the sense that I needed to be sure that backups can boot without a system-reset before going any further in my research. Now that I know it is possible, many things are worth considering in the next versions. The first things that come to my mind are the extra region protections  games can have (RGB/PAL protection, system broadcast check, etc.) then a in-game-reset that is working in all games. Finally, I am considering working on the bleemcast issue. As far as I know, it's the only game that does not like my bios....
Oh, yeah, speaking of that, I really need support. All my GD-ROM drives are broken and I need to get a new one. I would also appreciate if someone could make me an offer for a black Dreamcast, with its box. I am looking for an almost-new one (scratch-free). The US Sport Edition would even be better :) Well, it's time to let you download the "stuff" and enjoy it!

New features (for a long description, see the readme file):

  • SEGA License screen skip

  • MIL-CD/backup direct boot

  • Black fade-in color while booting from menu

  • No VMU copy-protected file check

And for those that don't really what I am talking about, I made a short video:

Update #1: someone gently reported that once a GDRom has been detected by the console, no MIL-CD/backup can boot up. GDEmu and UGC are fine though since they do not emulate the drive lock protection.I did not know that, so for now, until I'm able to test and either fix or disable the direct-boot feature, I remove the download links. Thank you.

Update #2: The next version V1.032 is almost ready. I'll put a release note about the MIL-CD issue you can experience. In the meanwhile, as some people asked, I put back the link to download the v1.031 release.

Next Dreamcast custom BIOS: W.I.P

Vacantions are almost over so it is time for me to get back to work. So many things to do!

A new version a GDRom Explorer should be released soon and as some people ask me for that feature, yes it will support a new format for Naomi users. That version will also fix a bug some users reported (thanks!) when extracting data. Basically, files with a specific size get corrupted after extraction. My program is unit tested but somehow I missed something. So I promise, the next version is going to be the right one ;) Regarding the version number, you will notice some changes. I should have used 1.7 instead of 1.6.2 for my last release. Thus I will jump directly to version 1.8 to stay consistent with my versionning policy.

Before my summer vacations, I published pictures of the next custom BIOS. It should have been able to display the disc name on the main screen but since I am facing issues I can't investigate right now, I've decided to postpone that feature. However, the next version will do the following:

  • skip the SEGA license screen (ready)

  • bypass the VMU file copy protection (ready)

  • allow MIL-CD/backup to boot directly without system reset (still working on that though)

  • maybe something else, don't know yet.

Enjoy a first teaser of the next custom BIOS!

In the meanwhile...

As many of you have asked for VGA/60hz patch for all the other language specific versions of Resident Evil: Code Veronica, here they come! Yesterday I decided to work on that but I spent most of my time writing makefiles so that one make command creates all the bin, ppf and nfo files for each language (english, french, dutch and spanish). To be honest, I hate makefiles, specially on the Windows platform (I'm using the official SEGA SDK to compile my patches... Don't ask me why :). I'm used to have all the linux tools handy so when I work on Windows it is frustuating; no sed, no grep, no simple way to manipulate strings, etc. Anyway, I eventually made it out.

Starting from now, I expect some people to start speed-running that game on Dreamcast! As far as I'm concerned, I don't go beyong the "press start button" screen, those survival-horror games scare me to death :)

Download links:
UPDATE: I remove the links for now since I've found something wrong: the game actually initializes the gfx stack another time, later in the game (at least one more time). It happens when you reach the room where you get the two golden Lugers. I will fix that a bit later. Thank you.

UPDATE #2: problem fixed :)

Snow Surfers EURO - 60Hz/VGA Patch

As I said in my previous post, I don't have much time to work on game patches or the next version of my custom bios. That though does not necessarily mean I can't quickly talk about what I worked on few weeks ago! I have a couple of game patches ready or almost ready and today I'm releasing an easy one. As usual, it is a 60Hz/VGA patch that you need to apply to the boot file (1ST_READ.BIN). Snow Surfers is one of those games that which have a specific name for each region: Snow Surfers in Europe, Rippin' Riders Snowboarding in the US and Cool Boarders Burrrn! in Japan. Not particularly helpful but funny though. It was one of the Dreamcast launch titles, at least in Europe. It is a pretty good game and playable up to 4 players.


Next and last point: custom bios. In addition to small patches that ease the Dreamcast's use, the next version of my custom bios will also embed two new features. One can easily be guessed from the pic below. For the other one, I let you imagine or wait, depending on your mood. I know that it looks a bit shitty but I need really more time to understand how I can re-use the internal graphics. (Time that of course I don't have...)