Modifying some error text on the Sega CD Bios. Turns out it's just plain text.

Out of Curiosity, and wanting to see how i could corrupt a bios beyond Recognition, i opened up my rom image inside a Text Editor, and noticed the Region error message glaring at me and i thought "It can be that easy... just change a few characters"...

Well, it was just that easy. it appears all of the text strings in the bios image are directly editable so, you can start with something like this:



and change it to this:



This was done on a Mega CD (J(E)) - M1 V1.00s Bios Image at addresses 0x00000767 - 0x000007B4. I don't know if it matters, but you may need to take into account the following:


Line 1 = 21 Bytes


Line 2 = 34 Bytes


Line 3 = 35 Bytes


I'm assuming you have to stay in that zone, but if someone wants to try expanding it go ahead. It just seems weird to me that this is just some random plain text, non-encrypted data that you can just modify. Pretty cool!

I haven't tried with other strings, but i plan to, and assuming this is editable we should be able to not only extract strings and such from the bios, but possibly any images, like the spinning Sega logo and/or backgrounds that they use on the boot screens, and even possibly the music; then replace it with new stuff.

 

Stuff that age and earlier is often plain text. In fact I think you'll find that a lot of "encryption" in things from early 90's and before is in fact compression or encoding. When memory cost a lot it made sense to compress. Or why use ASCII on a console that doesn't have a character set. So there's even more fun to be had once you work out how the data is encoded. Enjoy.

 

Yeah, the Dreamcast BIOS can very easily be edited as well. I've spent some time translating one of those strange obscure languages that no one ever uses (Italian or Spanish or something) into Danish. Worked really well, and it even supported the letters Æ, Ø and Å. Very easy to do, but then I remembered that I hate having Danish language on my devices, because they sometimes use retarded translations, and it turned out I couldn't do a better job myself

 

Shocking report - text is actually text.

News at 11.

 

Spanish is globally even more popular than English and Italian is right about 10 times as popular as the strange and obscure Danish.

 

I thought it was obvious that I was joking Should have put a smiley or something in there I guess...

 

Yes, "joking". Kul skämt, danskjävel