Truth be told, it was quite amusing to see what people came up with. Knowing that it was all true didn't make me feel offended or that my reputation was being dragged through the mud. Instead it even tempted me to delay the release a bit more, while releasing even crappier pictures. Sick? maybe, but loads of fun. Narf would gather every morning during the last week all the highlights of the day and send them to me. A very amusing read.
Actually, the biggest challenge was keeping Windows from assuming the video hardware is VGA compatible. The code in setupldr.bin which decides what system driver to load for video is rendered useless by some other code earlier which goes like this:
char* detectVideo() { return "VGA"; }
So you're stuck with vga.sys. Which in turn assumes there's a text mode. And yeah, it does probe the VESA BIOS to find out what SVGA modes it supports. But it adds to those the VGA modes, including the hateful, by now, text mode. Which setupdd.sys chooses as the best mode to setup in. Even though setupdd.sys is quite capable of using a linear RGBA graphics mode.
Replacing vga.sys is nearly impossible because of the layers of "security" added by layout.inf, driver signing (sp2.cat) and who knows what else. I ended up going with patching vga.sys in memory, and then replacing vga.sys with xomdd.sys using a registry hack.
So, in the end, it is those assumptions that caused Windows to be so hard to install. Figuring out what are the least bytes that need to be patched in order for this to work took 2/3s of the job. The other third was just the chore of implementing BIOS calls by mapping them to EFI.
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Truth be told, it was quite amusing to see what people came up with. Knowing that it was all true didn't make me feel offended or that my reputation was being dragged through the mud. Instead it even tempted me to delay the release a bit more, while releasing even crappier pictures. Sick? maybe, but loads of fun. Narf would gather every morning during the last week all the highlights of the day and send them to me. A very amusing read.
-blanka
Actually, the biggest challenge was keeping Windows from assuming the video hardware is VGA compatible. The code in setupldr.bin which decides what system driver to load for video is rendered useless by some other code earlier which goes like this:
char* detectVideo() { return "VGA"; }
So you're stuck with vga.sys. Which in turn assumes there's a text mode. And yeah, it does probe the VESA BIOS to find out what SVGA modes it supports. But it adds to those the VGA modes, including the hateful, by now, text mode. Which setupdd.sys chooses as the best mode to setup in.
Even though setupdd.sys is quite capable of using a linear RGBA graphics mode.
Replacing vga.sys is nearly impossible because of the layers of "security" added by layout.inf, driver signing (sp2.cat) and who knows what else. I ended up going with patching vga.sys in memory, and then replacing vga.sys with xomdd.sys using a registry hack.
So, in the end, it is those assumptions that caused Windows to be so hard to install. Figuring out what are the least bytes that need to be patched in order for this to work took 2/3s of the job. The other third was just the chore of implementing BIOS calls by mapping them to EFI.
-blanka