Before figuring out how to tackle this project, I needed to know whether it would even be possible. According to a 2021 Reddit comment:
There is a zero percent chance of this ever happening.
Feeling encouraged, I started with the basics: what hardware is in the Wii, and how does it compare to the hardware used in real Macs from the era.
I almost think such projects are worth it just to immortalize comments like these. There's a whole psychology of wrongness that centers on declaring that not-quite-impossible things will definitely never happen, because it feels like principled skepticism.
That used to be my thing: wherever our ops manager declared something was impossible, I’d put my mind to proving her wrong. Even though we both knew she might declare something impossible prematurely to motivate me.
My favorite was “it’s impossible to know which DB is failing from a stack trace”. I created STAIN (stack traces and instance names): a ruby library that would wrap an object in a viral proxy (all returns from all methods are themselves proxies) that would intercept all exceptions and annotate the call stack with the “stain”ed tag.
I've seen more than one half-joke-half-serious chunk of code that would "encode" arbitrary info into stack traces simply by recursively calling `fn_a`, then `fn_s`, `fn_d`, and `fn_f` before continuing with the actual intended call, giving you a stack trace with (effectively) "asdf" in it.
They've also been useful more than once, e.g. you can do that to know what iteration of a loop failed. There are of course other ways to do this, but it's hard to beat "stupid, simple, and works everywhere" when normal options (e.g. logs) stop working.
Similarly, one of the great things about Python (less so JS with the ecosystem's habit of shipping minified bundles) is that you can just edit source files in your site_packages once you know where they are. I've done things like add print statements around obscure Django errors as a poor imitation of instrumentation. Gets the job done!
Well you're doing gods work as far as I'm concerned. Conflating difficulty in practice with impossibility in principle is, to my mind, a source of so much unnecessary cognitive error.
They're kinda like high-effort shitposts. Which are my absolute favorite kind. The worse the effort/reward payoff, and the more it makes you ask "WHY??!!?", the better.
Wasn't the old Linux joke, don't ask "how do I do X with Linux" (because you'd get ridiculed for not reading the docs) but instead, just state "X isn't possible with Linux" and then someone would show you how it's done?
As the author of the NetBSD Wii and Wii U ports, congrats! I’m looking forward to seeing how you solved some of the problems that I faced along the way.
Not only is this an insanely cool project, the writeup is great. I was hooked the whole way through. I particularly love this part:
> At this point, the system was trying to find a framebuffer driver so that the Mac OS X GUI could be shown. As indicated in the logs, WindowServer was not happy - to fix this, I’d need to write my own framebuffer driver.
I'm surprised by how well abstracted MacOS is (was). The I/O Kit abstraction layers seemed to actually do what they said. A little kudos to the NeXT developers for that.
I felt similarly. The learning curve was a tad steep, especially since I had never written a driver before, but once I figured out how to structure things and saw the system come alive, I grew to appreciate the approach IOKit takes.
With that said, I haven't developed drivers for any other platforms, so I really can't say if the abstraction is good compared to what's used by modern systems.
IOKit was actually built from the ground up for OS X! NeXT had a different driver model called DriverKit. I've never coded against either, but my understanding was they're pretty different beasts. (I could be wrong)
That said, indeed, the abstraction layer here is delightful! I know that some NetBSD devs managed to get PPC Darwin running under a Mach/IOKit compatibility layer back in the day, up to running Xquartz on NetBSD! With NetBSD translating IOKit calls. :-)
There’s a great video of a NeXT-era Steve Jobs keynote floating around—I think the one where he announces the x86 port as NeXT was transitioning to a software-only company—where he specifically calls out DriverKit and how great it is.
Steve was not a developer but he made it his business to care about what they cared about.
Yes, you're right! I'm just dolt who's never checked what a .kext on OS X actually is.
I had been under the impression that DriverKit drivers were quite a different beast, but they're really not. Here's the layout of a NS ".config" bundle:
OS X added a dedicated image type (MH_KEXT_BUNDLE) and they cleaned up a bit, standardized on plists instead of the "INI-esque" .table files, but yeah, basically the same.
IOKit was almost done in Java; C++ was the engineering plan to stop that from happening.
Remember: there was a short window of time where everyone thought Java was the future and Java support was featured heavily in some of the early OS X announcements.
Also DriverKit's Objective-C model was not the same as userspace. As I recall the compiler resolved all message sends at compile time. It was much less dynamic.
And there are enough parallels to Linux's stack, I'm thinking about looking through the Linux on Wii project more and comparing how it handles fb issues in comparison. I loved reading this whole post, crazy how many OSes have now been run on the humble Wii!
I probably have rose colored glasses, but this is what I associate with Hacker News when I first started coming to this site. Truly absurd projects for no reason other than the love of the game and detailed write ups.
I'm not an LLM post hater, but it definitely has been a bit draining lately. This is exactly what I love to see here.
I’m SOO happy but also wistfully sad when I open a post like this that I am desperately excited to read and it’s not muddled-thinking- and LinkedInese-riddled slop.
This is the most incredible part. I cannot even use a laptop adequately in an economy class seat, I cannot position the screen so that I could see it, and the keyboard so that I could type on it, at the same time. (To say nothing of connecting a Wii.)
I can't imagine concentrating on a complicated project like that on the go, but I went back to stare in awe at said picture and I think its a train or bus. Still a flex.
What's flex-worthy about this? There's a lot of dev work that goes on in economy class airplane seats. Or are VC valley programmers so rich they fly business everywhere?
It's uncomfortable and awkward (the Wii was on his leg in the first shot), and often you need to break concentration and pack things up to let someone out of or into their seat.
So what you're saying is if it's flexing, it's entirely performative. gotcha.
I don't think that's a healthy way to look at it - dude was just getting some work done, but maybe I'm a broken human being who's churned out more code than I would ever admit while sitting in 32C on a cross-country flight.
Another funny history fact with the Wii is Windows Vista released the same month in North America. People were so upset that the minimum requirement for Vista said 512 MB (which was already more than the average existing home PC of the time had without an upgrade) but it ran like crap unless you had more.
We truly had to get away with less back then. These days it feels like there is a bit more headroom where 8 GB is on the downtrend, 16 GB is becoming the most common, and the user's apps are enjoying the extra fat.
Back in the day I was a hardcore Mac nerd and became a professional at it too. My best reverse-engineering trophy was building one of the first "iOS" apps when there was not an official appstore for the iPhone.
But man, this is way ahead of what I could do. What this dude accomplished blew my mind. Not only the output (running MacOS on a Wii), but the detailed post itself. A-MA-ZING.
Debugging kernel panics on a Wii in an economy seat is a level of focus I can't even imagine. Most people can't read a book on a plane without losing their place every 5 minutes.
As someone who's been trying to do something VERY similar (port Mac OS 9 to the Nintendo Wii U), all I can say is I'm 1) absolutely impressed, and 2) absolutely encouraged, as my project keeps telling me "this is impossible" at every opportunity.
YUV appears to be a PAL-specific color space. I wonder how off an NTSC Wii would be. Presumably it would have the wrong color space until an equivalent conversion scheme was devised for NTSC.
I was surprised to see regional color spaces leak into the project, but I presume that Nintendo's iOS (the coincidentally-named system this is replacing) could handle that abstraction for game developers.
That's true in broad strokes, but looking into it, it turns out NTSC's variant of YUV is called YIQ, and SECAM's variant is called YDbDr. They are however all more or less the same thing, and the digital YUV used by the Wii hardware in this case is presumably independent of the video standard.
The one that really bugs me is the Apple TV. It would be a great little box to use for terminals/thin client style work and there are a ton of old cheap ones. Having a $50 dollar used box that was low power and could run OSX would be great.
The original one does run a modified OS X Tiger. I jailbroke it a while ago to run custom stuff, but didn't do much with that. Just remember being able to VNC or SSH into it.
A side note: you embedded .mov videos inside <img> tags. This is not compatible with all browsers (notably Chrome and Firefox), which won't load the videos.
Minor usability comment: the screenshots are too small to be readable. Whenever that's that case in my blog posts, I make those screenshots clickable and add (Click to enlarge) below it, to make it easier for readers to see the image are original resolution. In markdown, I do that like this:
[ ](image_url.png)
(Of course, I can also right-click and do "Open image in new tab", but that's one click extra...)
Congrats on the awesome project, BTW! You were lucky that I wasn't sitting next to you on the plane. I would have wasted so much of your time asking dumb questions.
This was an incredible read! Especially for what looks like the first post to this blog too? I wanted to subscribe to the RSS feed but unfortunately it gives a 404 error.
The Wii is very moddable. I've modded my Wii in the past just for playing modded versions of Super Smash Brother Melee (mainly training packs, like flashing a red light when I miss an L-cancel).
I wrote that L-cancel training code! Funny to see it come up out of nowhere. I too have always adored the Wii and its moddability. It'd be my go-to choice if I someday ever get the itch to write console homebrew software of my own.
Yes - this project (and countless others) would not have been possible without the incredible work to hack the Wii from Team Twiizers (now fail0verflow) back in the day. The work they did was a huge inspiration for me getting into computer science when I was a teenager.
I wonder if you can place an A18 from a Neo onto an iPhone board, and then make that work somehow... You wouldn't be able to use the one originally from the iPhone because it's differently fused to only accept iOS images.
This is extraordinary, not only pushing the limit but documenting everything so clearly to show people what can be accomplished with time and dedication. Thank you for such thorough documentation, and congrats on getting it done!
Given that the original Apple TV ran on a modified version of macos, what are the chances one could turn an old wii into an Apple TV..?
EDIT: also, I just noticed on a second pass the system is addressing 78mb of ram, potentially meaning the ram spans the gddr3 and sram, I'm amazed this works as well as it does with seemingly heterogeneous memory
I'd say there is a zero percent chance of this ever happening :D
The original Apple TV was an Intel Core Solo with 256 MB of RAM and an nVidia GPU, running a modified Mac OS X 10.4 that booted into something similar to Front Row instead of Finder.
Oh interesting, it looks like that geforce had an entire 64mb of gddr3 too, it'd still be fun to see if one could limbo that low, though I agree that save for upgrading the BGA ddr3 of the wii to something more the size of the dev kit had(128mb GDDR3)
They are successfully porting Mac OS onto every kind of modern computer over at the hackintosh subreddit, and I can't understand why there is so little interest for this stuff in the "hacker" sphere.
Surely, it must be a better option than Linux if you want to get the most out of a PC computer? At least for 10 more years.
I'm not sure why it would. Why would anyone want to hack on different proprietary software with no supplier support and whose days are clearly numbered (Apple's move to ARM)?
For usability I mean. It's clearly an interesting technical feat.
Because it has all the advantages of Linux + all the advantages of Windows + many advantages of its own.
So to have a fully fledged and more usable computer, for those who don't want to purchase the Apple hardware.
And the latest Mac OS still supports Intel, so you'll get many more years out of a machine. For what I know, the last 10 versions of MacOS are still very usable.
I bet if me-20-years-ago knew that current me would have no fucking clue how to even begin to tackle a problem like this, me-20-years-ago would be very disappointed. Very jealous of your expertise. Awesome work!
Exceptional work. While it may not mean much, I am truly impressed. I like to toy with reverse engineering here and there, but such a port like this would take me multiple lifetimes.
Not to distract too much from the main topic, but what do you think about the Hopper disassembler? I have only used Radare2, IDA Pro, and Ghidra. Though, I haven't used the latter two on MacOS. What do you prefer about Hopper? I have been hesitant to purchase a license because I was never sure if it was worth the money compared to the alternatives.
I like using it for disassembling UIKit (for my day job working on iOS apps), and overall, I like the UI/UX and how it feels like a native Mac app.
I've tried Ghidra, and while extremely impressive and capable, it might be the most Java-feeling app I've ever used. I'd love for someone to whip up an AppKit + SwiftUI shell for it.
There are bugs and undocumented behaviors that need to be understood in order to be worked around - I wish it wasn't the case but such is life developing for closed-source platforms.
> I like using it for disassembling UIKit (for my day job working on iOS apps), and overall, I like the UI/UX and how it feels like a native Mac app.
You are correct about the UI/UX. I do think Hopper is ahead of others in that regard. Though, Radare2 being a CLI tool is nice as well. Though, I haven't attempted to use Radare2 for MacOS/iOS disassembly. Though I must ask, why are you disassembling UIKit? Looking for private API behavior or working around bugs? I've been learning more about iOS in my spare time, because despite my love for Swift, I have never used it for iOS. I only have used Swift for MacOS automation, i.e., AppleScript replacement via the Accessibility, Core Foundation, AppKit, etc..
> Ghidra, and while extremely impressive and capable, it might be the most Java-feeling app
I chuckled while reading this because I had the exact same thought when I first used Ghidra. I haven't tried Ghidra on MacOS because I will not taint my machines with the impurities of Java. I also do not want to enable Rosetta, so that was another obstacle in trying Ghidra on MacOS. In Ghidra's defense, using Java was a pragmatic choice. The "write once, run anywhere" promise of Java is likely a near-necessity for a disassembler for government operations.
The post is a work of an actual hacker who knows what they're doing. Zero mention of "I used Claude" or "Used AI" to understand what is needed for accomplish this task.
This is exceptional work. Unlike the low-effort slop posts I see here on "Show HN".
I used plenty of non-agentic AI to help understand the XNU codebase, and also research various topics. It wasn't always correct, but it certainly helped at times! My philosophy for this project was to use it as a learning tool - since that was kind of the whole point of me attempting this :)
Absolutely nothing. People protest Github to virtue signal their anti-Microsoft sentiment and fill a hole in their personality.
Similarly, "zero mention of AI" is just a surface-level observation that says nothing about how the project was completed and everything about your own insecurities defining the word hacker.
This solution’s COU cost can be significantly improved by using memory protection. You protect the frame buffer from writes. The first time it is written, you take a fault, and start refreshing every 60 Hz and leave it writeable. After some number of refreshes, you protect it again, the idea being is that the UI may now be quiescent. I do this in my Palm OS port for the same reason.