[HN Gopher] Linux Runs on Raspberry Pi RP2350's Hazard3 RISC-V C...
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       Linux Runs on Raspberry Pi RP2350's Hazard3 RISC-V Cores (2024)
        
       Author : walterbell
       Score  : 141 points
       Date   : 2026-01-03 16:34 UTC (6 days ago)
        
 (HTM) web link (www.hackster.io)
 (TXT) w3m dump (www.hackster.io)
        
       | sylware wrote:
       | I wish I could buy RP2350 with the ARM cores being hard-fused
       | disabled, "cheaper" since no ARM royalties would have to be paid.
       | 
       | That said, I wonder how much they did improve their hazard3
       | design, because we all know the future is no PI locked ARM cores.
       | I wonder if they are sharing part of the design of other open
       | source RISC-V cores.
       | 
       | If those efforts are kept significant, the future is looking good
       | and better there. Hopefully, all that will be a success (=latest
       | silicon process, ultra-performant RISC-V implementation in
       | mobile/embedded/desktop/server).
        
         | danhor wrote:
         | The Hazard 3 is _basically_ a hobby project of Luke Wren, a
         | Raspberry Pi Employee. He 's contiuing to evolve it further,
         | but I don't think it's ready for a full replacement of the
         | Cortex-M yet, especially in regards to the Security Features.
         | 
         | The source code is all from Luke Wren and I don't think other
         | cores use the source code directly, but improvements to test
         | harnesses or general implementation patterns as well as better
         | software support help other cores:
         | https://github.com/Wren6991/Hazard3
         | 
         | For the SoCs I would expect to see an off-the-shelf Risc-V core
         | (certainly no Hazard3 as the main CPU), but we'll see.
        
           | sylware wrote:
           | linux started as a hobby project...
           | 
           | I am curious to know which RISC-V design they'll go for in
           | this SOC.
           | 
           | M. Wren getting real hard experience on RISC-V is going only
           | to help RP to select and audit more seriously any RISC-V
           | design which would make its way in their SOCs.
           | 
           | I just don't want to contribute to arm IP racketering (and we
           | have mpeg and hdmi to take into account too with avX and
           | eDP/DP).
        
           | Findecanor wrote:
           | The Hazard3 in the Pico 2 are bigger, more capable cores than
           | the Cortex-M0 in the first Pico, and therefore in general
           | faster at the same clock for compiled code.
           | 
           | You're supposed to be able to just recompile most Pico
           | projects to use them as long as there is no ARM assembly in
           | it.
           | 
           | They are only inferior to the ARM Cortex-M33 cores in the
           | Pico 2.
        
             | PunchyHamster wrote:
             | So they come inferior in the only place it matters, gotcha
        
           | ipdashc wrote:
           | I know the "basically" is probably doing a bunch of heavy
           | lifting, but dang, that's still awesome to think about. I
           | didn't know hardware development was at the point where a
           | hobby project CPU, apparently mostly developed by one guy,
           | can realistically end up in a mass produced product like
           | that.
           | 
           | Quick edit: sounds like "basically" wasn't doing that much
           | heavy lifting after all, wow
           | https://www.raspberrypi.com/news/risc-v-on-raspberry-pi-
           | pico...
        
         | Tharre wrote:
         | You can probably already get that if you order a somewhat
         | significant amount of chips directly from Raspberry Pi. They
         | seem to already have everything required for it, it's literally
         | just setting a bit differently during factory programming.
         | 
         | But I'm assuming you're talking about for consumer use, in
         | which case my question is why? There is absolutely no way
         | you're ever benefiting from them spinning up an extra SKU with
         | significantly less volume (most people want the ARM cores).
         | 
         | Even if they decide to eat the costs for the benefit of
         | consumers, at most the chip would be what, 15 cents cheaper? I
         | really struggle to see how that's a meaningful difference for
         | hobbyist use.
        
         | phkahler wrote:
         | >> I wish I could buy RP2350 with the ARM cores being hard-
         | fused disabled, "cheaper" since no ARM royalties would have to
         | be paid.
         | 
         | Better yet, put 4 RISC-V cores on there!
        
       | rmu09 wrote:
       | It would probably make more sense to target something like this
       | https://www.hackster.io/news/andrew-bunnie-huang-prepares-th...
       | with linux, has MMU and more RAM.
        
         | sho_hn wrote:
         | This one runs Linux on the ARM cores rather than the RISC-V
         | cores in the same package, so it's apples and oranges, but
         | still pretty neat for something that comes essentially with a
         | companion MCU and is in the same form factor:
         | 
         | https://milkv.io/duo
         | 
         | In embedded systems it's very common to have a bigger SoC and a
         | satellite MCU to handle e.g. network comm and power lifecycle.
         | I've still not really tried out my Milk-V Duo, but it's
         | interesting to get a combo like this in a hobbyist board form
         | factor.
         | 
         | They also claim desktop-class performance for this RISC-V-based
         | miniITX board, it's a bit weird though since it doesn't claim
         | RVA23 compliance:
         | 
         | https://milkv.io/titan
        
           | arjunbajaj wrote:
           | I'm building Fostrom (https://fostrom.io), an IoT Cloud
           | Platform. We have Device SDKs to simplify integrating
           | devices, powered by a small Device Agent written in Rust.
           | 
           | I wanted to support RISC-V boards too, so I went with the
           | Milk-V Duo S as the test device. I have managed to get
           | Tailscale working, and our Device SDK works too, with the
           | bundled Python.
           | 
           | The experience of using the Milk-V Duo is definitely not as
           | straightforward as the Pi Zero, but it does work, and is
           | easily available in most places, unlike some of their other
           | products. The Linux distro they provide is quite barebones,
           | and I wasn't able to get Debian working. The docs for the
           | device are pretty decent. I hope we get better support for
           | Debian/Alpine/Arch for these kinds of boards soon.
        
         | jacquesm wrote:
         | Availability is a major factor in projects like this.
        
       | jokoon wrote:
       | I don't even know what would be the point of such device, and if
       | there really is a market for it for tech companies. I would say
       | yes?
       | 
       | As a consumer, all I want if a very minimal "phone", with wifi,
       | touch screen, battery, but no 4g or mobile networking, and linux
       | on it. Just the cheapest, smallest, wifi, battery-powered,
       | touchscreen LCD device that could exist that can run executables.
       | 
       | People are going to say "but just buy a cheap phone", but I
       | cannot really run custom software on those, I can't expect to
       | install a custom system image, and generally even cheap phones
       | CPU SOC are way way too powerful. Open source phones are
       | generally crazy expensive and very powerful, and I am not going
       | to buy those.
       | 
       | With the range of hardware that exist out there, I think such
       | device could cost about 60 euros, and it would be more
       | interesting than a RPI.
       | 
       | The RPI is an amazing product, but it lacks an all integrated
       | consumer device with an actual screen and battery. Of course I
       | can already build one with a compute module etc, but it's not
       | really portable and not designed around a flat battery.
        
         | tecleandor wrote:
         | First, note that what's on that article is not an Raspberry Pi,
         | it's a Raspberry Pi Pico.
         | 
         | I'm not sure about what you want. You don't want a phone, so
         | you want... A tablet, maybe? Or a Raspberry Pi 3/4/5 with a
         | touch screen? Do you want a small screen? Big? Keyboard/Keypad?
         | Touch only?
        
         | bee_rider wrote:
         | They don't make cellphones, they make little computers.
         | Hypothetically you could probably use an Arduino or an esp32 to
         | make a cellphone, but you wouldn't say those organizations lack
         | an all-integrated consumer device, right? They just aren't in
         | that business.
        
         | mghackerlady wrote:
         | You can buy touchscreen enclosures for the various pi models.
         | If you want to put in the effort to make your own PCB you could
         | really slim it down by using a pi compute module
        
         | numpad0 wrote:
         | > I think such device could cost about 60 euros
         | 
         | Making a thing made, shipped and delivered at 60 euros each on
         | credit cards is HARD. 600 is easier. 60m consider it done. I
         | wouldn't want to even make and sell, idk, a lens cap for a
         | camera, at that price, without first owning couple factories
         | running at healthy levels of utilization. Maaaaybe if my
         | customers would be happy with a 3D printed artisanal version of
         | it. But even then it'll technically be delivered at a slight
         | loss.
        
       | PunchyHamster wrote:
       | after https://dmitry.gr/?r=05.Projects&proj=35.%20Linux4004
       | nothing's really impressive when it comes to making it run linux,
       | doubly so that it runs just normal Debian userspace
        
         | ge96 wrote:
         | What about Commodore where it took 7 hrs to boot (video YT)
         | 
         | Edit: oh damn this one is even worse 8.4 days ha
        
         | mosura wrote:
         | That is too practical. For ultimate HN bait it needs to include
         | Rust deployed (over QUIC) as WASM on RISC-V.
        
           | IgorPartola wrote:
           | But the CPU needs to be build in Minecraft.
        
           | apitman wrote:
           | Rust and QUIC are bloated, but I'll take WASM and RISC-V
        
         | RobotToaster wrote:
         | Has anyone run linux on thermionic valves yet?
        
           | dmitrygr wrote:
           | I'm on it
        
             | balou23 wrote:
             | You'd better be, we have certain expectations from you now
             | /s
             | 
             | But more seriously... I don't think that Linux has ever
             | been booted on a non-monolithic CPU (I wanted to say
             | 'discrete cpu' first, but there's some PDP-11s with 4 chip
             | CPUs)
        
               | dmitrygr wrote:
               | one could argue that 4004 is it. It does not really do
               | memory ops at all. all decoding for memory ops happens
               | inside the memory chips. but yeah - not non-monolithic
               | enough
        
         | b00ty4breakfast wrote:
         | Is that the same Dmitry that got the linux kernal to run on an
         | atmega?
        
           | PunchyHamster wrote:
           | also on 3 8 pin chips. I listened to interview with him and
           | he decided to wait 10 years to give competition a chance then
           | try to do it on raw transistors or vaccuum tubes
        
         | hdndndb wrote:
         | Running native vs running under emulation is a complete
         | different beast
         | 
         | Any turning machine can boot Linux under emulation
        
           | PunchyHamster wrote:
           | turing machines are far superior to 4004 to, normal machines
           | don't have infinite memory for example
        
           | nxobject wrote:
           | ...Linux nommu, and the system busses of these platforms,
           | won't get the complete environment that Dmitry wants,
           | unfortunately.
        
         | Perz1val wrote:
         | Linux in PDF was impressive in a different way
        
       | mghackerlady wrote:
       | I'd really like to see a pi zero 3 that runs on RISC-V, it might
       | be the kick in the pants RISC-V needs to go "mainstream" at least
       | in the public view. People know raspberry pi, nobody outside the
       | RISC-V scene really cares or even knows about MILK-V
        
         | eek2121 wrote:
         | RISC-V needs an inexpensive, performant part for it to be used
         | in the consumer space.
         | 
         | The fastest available RISC-V consumer chip is orders of
         | magnitude slower than a Raspberry Pi 5. Example:
         | https://browser.geekbench.com/v6/cpu/compare/15998376?baseli...
        
       | lenerdenator wrote:
       | So we've got a truly free OS; how free is this implementation of
       | RISC-V?
       | 
       | Honest question, I don't follow much on the hardware front.
        
         | Zhyl wrote:
         | It's an open source core design [0], so pretty open.
         | 
         | [0] https://github.com/Wren6991/Hazard3
        
       | walterbell wrote:
       | Linux on Pi Zero can be used as a sidecar for iPads.
       | 
       | https://schwarztech.net/articles/my-ipads-raspberry-pi-sidec...
       | This method configures the Raspberry Pi [Zero] in "gadget" mode,
       | creating a private link that appears as a wired Ethernet
       | connection over a USB cable. The Pi's address will never change,
       | either as it is also a DHCP server for the iPad. As an added
       | bonus, the same cable powers the Pi, creating a setup as simple
       | as plugging the Pi into your iPad and waiting for it to appear ..
       | you have a full-blown Linux computer working in tandem with your
       | iPad and the iPad acting as a directly-connected console that is
       | also providing power.
        
         | 0x457 wrote:
         | Any non RP2xxx pi can be used like that. Unrelated to this post
         | at all? I only fall back to that when there is no interwebs,
         | otherwise connecting over ssh to a normal server is far more
         | productive.
        
         | Aurornis wrote:
         | The Pi Zero is a full SoC which naturally runs Linux. Any Linux
         | SoC with USB (so basically all of them) could use used in the
         | same way.
         | 
         | This article is about the RP2350's microcontroller cores. It
         | doesn't even have an MMU, so running Linux on it is much more
         | interesting. It's not as capable as the normal Linux we run on
         | bigger boards, but it's still interesting.
        
           | walterbell wrote:
           | Could Linux on RP2350 cores work with iPad via Pi Zero form
           | factor, with microSD storage to supplement iPad?
           | 
           | https://www.cnx-software.com/2025/07/08/rp2350-pizero-
           | rp2350...
        
         | ge96 wrote:
         | Gotta get Pi Zero 2, way stronger hardware
         | 
         | side note: I wish it had more ram so you could mount it in VS
         | Code vs. developing through SSH
        
         | panzagl wrote:
         | Thanks for linking this, I would not have expected this usage
         | (more from the iPad side being locked down) and it has inspired
         | some thought.
        
           | walterbell wrote:
           | It can be used to mirror content for offline viewing, e.g.
           | share sheet sends URL to iOS shortcut, which uses SSH to send
           | yt-dlp or wget archive command line to Linux sidecar, which
           | has microSD storage (more capacity, lower cost/GB). Linux can
           | host WebDAV/CalDAV and SFTP content for iPad apps and media
           | players.
        
         | MomsAVoxell wrote:
         | I carry around an pwnagotchi[1], it serves not only as a cute
         | little paper display, but also a battery powered Linux box.
         | 
         | Can do everything you wanna do, in a cute little box attached
         | to a backpack.
         | 
         | My battery lasts about 3 hours, but its easy to juice it up if
         | we go hiking and need a common filesystem up some mountain
         | somewhere, know what I'm saying ..
         | 
         | (PS - the pwnatotchi part is just an app you can disable if you
         | just want your Linux box to be a Linux box, but it sure is a
         | fun little toy also ..)
         | 
         | [1] - https://www.thingiverse.com/search?q=pwnagotchi
        
         | mbreese wrote:
         | I used to do the same thing with a full RPi4. I'm pretty sure
         | that was the first non-pi zero that worked in gadget mode.
         | 
         | I was trying to make an attached Linux machine for my iPad
         | instead of using a cloud VM. It was pretty effective, but at
         | the time the ARM distributions were difficult to run what I
         | wanted. Now, however, it would be significantly better.
        
           | walterbell wrote:
           | Going in the other direction: recent Intel laptops with
           | Thunderbolt should support USB gadget mode. In theory, this
           | would allow a Linux laptop to emulate keyboard and mouse
           | input to an iPad Mini portrait sidecar, with seamless
           | kb/mouse context switching onto USB, as the cursor moved into
           | the configured virtual viewport of the iPad "monitor".
           | 
           | Similar to synergy/barrier/input-leap, but using USB gadget
           | mode instead of local network, since iOS wouldn't allow
           | installation of non-Apple keyboard-mouse remoting software,
           | https://github.com/input-leap/input-leap
        
       | fsiefken wrote:
       | Alternatively the RP2350 can also run Fuzix
        
       | wbsun wrote:
       | Oh running Linux on a MCU without MMU.
       | 
       | I feel there is a gap between MCU and modern CPU, and also
       | between the software running on top of them. The missing piece is
       | a mid-size computer with: - A processor, single or multi-core,
       | with computing power like 20 years ago, but modern fabrication
       | process. Maybe without MMU for simplicity. - RAM between
       | 100MB~1GB and DDR2/3 bandwidth. - An OS designed and implemented
       | for this type of hardware rather than tailored Linux.
       | 
       | I don't think you can use it for working or your daily
       | entertainment, so I guess not a good business to attract
       | interests.
        
         | synack wrote:
         | That was Intel Quark. It was too expensive for the "big
         | microcontroller" use case and too power hungry for the "small
         | Linux" use case.
         | 
         | The marketing was confusing, I'm not sure Intel even knew what
         | it was for, except to show investors they had an IoT play.
         | 
         | https://en.wikipedia.org/wiki/Intel_Quark
         | 
         | I found some of these boards in a box last year and was unable
         | to do anything with them... Intel has thoroughly erased all
         | documentation and SDKs from the internet. If anyone has those
         | artifacts, please push to archive.org
        
       | itomato wrote:
       | Buildroot is awesome and deserves more love
        
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