![]() I do wonder if there aren’t still some flaws (the Tecmo logo looks rather rough) but it could be right (see next statement), and the title screen definitely looks fine. Previously both these graphics (the Tecmo logo and entire title screen) were displayed as garbage because they’re both compressed and encrypted. I poked around with the multiple block side of things a little, and eventually we’ve ended up with this The encryption implementation, as it turned out, was missing some important details, features that none of the Naomi games really used (multiple encrypted/compressed blocks in a stream with mid-stream headers, non-power of 2 sizes for compressed data etc.) furthermore our encryption implementation was incomplete, so Andreas needed to further study the data and fill in some gaps. ![]() Software to extract data for analysis from a Naomi board already exists, and it turned out that by transplanting one of the chips from an ST-V cartridge onto a Naomi board we could use the existing extraction code and obtain a key thus confirming the chips were exactly the same thing just programmed with different keys. It was discovered by ANY and others that many of these boards used a 315-5881 chip, we’d long suspected it could be the same scheme, but had never actually managed to make a firm connection. ![]() In many cases these were used as a simple protection (especially on Model 2 / 3 and Radiant Silvergun in STV) just writing some values, reading them back and comparing them against a string in the code (which is very easy to bypass) but the reality is that there is a chip performing rather complex decompression and decryption operations on the data written in order to get that result, and in some cases it was actually used properly! If you’ve been following recent news / various GIT commits then you might have noticed that we recent connected the dots between the encryption/compression schemes used on Naomi carts and those used on other Sega systems (ST-V, Model 2, Model 3) etc. ![]()
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