Reverse Engineering All the Raspberry Pis | Hacker News Reader

Reverse Engineering All the Raspberry Pis

jeffgeerling.com

142 pointsspeckx39 comments

The Lumafield scans images are pretty, but I did not see any complete copper runs showing, as were clearly visible in the release by TimeTube. So I doubt the Lumafield scan data would be anywhere near as useful as the TimeTube data drop.

nitpick: It's TubeTime, not TimeTube

Why doesn’t the foundation release schematics? Their moat is buying hundreds of thousands of SoCs from broadcom, not their motherboard designs.

Because Broadcom.

It seems the biggest success of the foundation is to whitewash Broadcom's image and further normalise closed proprietary systems that have the appearance of being open.

Does there exist an RPI clone built around a SoC that is suitably open?

I believe most of these have public (or made-public) documentation available for their SoCs: https://en.wikipedia.org/wiki/Banana_Pi

But for real openness, nothing beats an older x86 PC.

Maybe they've improved, but banana pi/sinovoip used to ship images based on android kernels.

Rockchip have a reputation of fully working with the open source community, though I can't personally say how well. Most other SoC vendors only do enough to get android going.

Given that Android is basically the most popular "distro" of ARM Linux, that's not surprising.

However, I was referring to the availability of documentation which for these Chinese SoCs is either officially released or soon leaked.

Leaked SoC documentation is a very long distance from having a fully working open ecosystem. Like, dozens of man-years -maybe hundreds. It would be a mistake to assume you can pick any of the sinovoip boards and get that. They use a number of SoC vendors with very different business models, and level of support for FOSS. Certainly there are some who make much less investment in maintaining an open ecosystem than RPI.

x86 PCs need insecure and ordinarily impossible to replace blobs in order to boot. It's true that PC firmware doesn't seem to hurt open source people's feelings quite so much as it once did, but there's not a ton of logic to that.

Coreboot has been around for over a decade.

I'm not taking the "security" bait at all, especially when we're comparing a PC to an even less-explored platform which also requires binary blobs.

Unless things have changed significantly coreboot is an example of what I'm talking about - not a ton of x86 motherboard hardware is supported very well. "But for real openness, nothing beats an older x86 PC" just doesn't seem true at all.

(but I'll look into coreboot. I'd get a kick out of trying it.)

RPi-Pico2 uses the RP2350 which has two cores, one is a RISC-V core, and its source code was released on GitHub.

That's a microcontroller.

Both cores are actually ARM cores, but you can switch both cores to be RISC-V cores as well on boot.

Technically that's four cores, two of which that can be active at once

Are there any good truly open SoCs out there? Seems like it's impossible to find even a single chip that doesn't require some proprietary blob to work, let alone good chips.

Pine64 boards tend to be more open, but not fully, as they compromise between openness and price.

I think that's a bit harsh. The bulk of the Raspberry Pi audience has no idea of the Broadcom connection. They're kids (like mine) who are looking for a cheap computer to do their hardware hacks with. And a Raspberry Pi Pico is very hard to beat for the money, they're ~5 bucks here single quantity, and far more powerful than Arduinos (and cheaper!).

The competition for "very hard to beat for the money" hasn't been Arduinos for decades; it's cheap ARM Cortex boards, e.g. STM32 Nucleo - or ESP32.

I think ESP32 is really the one to beat.

Arduino have been lazily cashing in on their brand name for many years.

Is there a good comparison site anywhere for boards nowadays?

I still usually gravitate to the Pi or Arduino, but mostly due to a combination of lack of familiarity with other brands, and being a repeat customer for stuff that just works

I don't think so. Mbed used to have a nice one for all the boards that support Mbed, but that's dead now.

Looks like Zephyr has an extremely comprehensive list: https://docs.zephyrproject.org/latest/boards/index.html

Doesn't include prices though, and it's really too comprehensive - it seems to include lots of boards you can't actually buy. So maybe not very useful for finding good boards.

What’s a “good” RiscV board to start using for small projects?

Looking for a successor to the RPi - good documentation, easy to write bare metal for (no SDK), no surprises.

ESP32-C6, and associated dev boards.

>The bulk of the Raspberry Pi audience has no idea of the Broadcom connection

That doesn't make it less true. The GPU/VPU on the OG RPI was always undocumented and closed source that the community had to reverse engineer drivers for. Big L from my side for that.

It's why the OG RPI felt to me like a sneaky way Broadcom could move the stocks of unsold inventory of those set-top-box chips by marketing them as "Linux computers" that pretend to be open source but are actually not. Big brain move on their end to be fair.

> The GPU/VPU on the OG RPI was always undocumented and closed source that the community had to reverse engineer drivers for. Big L from my side for that.

So, like pretty much every other consumer level GPU?

Consumer GPUs aren't marketed as open source learning and tinkering boards.

That's fair. At the same time: the foundation and Broadcom really are two separate entities and I think even Broadcom is surprised by how successful the whole thing is. They may have thought to just humor their employee but it has become something much larger than that now. And I do agree they should open it up, just that that is not in Broadcom's commercial interest as far as I can determine.

looking for a cheap computer to do their hardware hacks with

A free standard PC, of which a depressingly large number are thrown out every day, easily beats the price and performance of an RPi, in addition to being far more open.

…while being hundreds of times bigger and also not offering the scope to implement hardware hacks (e.g. interfacing through GPIO/I2C/SPI/Serial without additions that cost more than the entire Pi).

Yes - obviously you can use an old PC for many different PoCs and prototypes. It doesn’t take much imagination to think of those you can’t.

> not offering (...) GPIO/I2C/SPI/Serial

Nearly every "old PC" does offer built-in easily accessible I2C - as "DDC channel" of a monitor plug - VGA, DVI, HDMI, DisplayPort - all have it. Linux exposes those as regular /dev/i2c-*, so any I2C software that works on a RPi or other Linux SBC, will run with those too:

https://web.archive.org/web/20120903090802/http://www.painty...

Also there are usb devices that can run gpio/spi/i2c/uart for a few bucks.

What does Broadcom have to do with the motherboard layout?

The pinout of the CPU itself might be under NDA (just speculating). Or some interconnection details, or who know what other information you might get from the schematics.

yes, most likely this is the case. also for the ethernet phy. there's really no good reason for it; these pinouts are pretty bog standard. chalk it up to corporate paranoia.

Take a closer look at the history of how they've been running things pretty much since the beginning. Even though they give away a lot of code under open source licenses (most of it they have to), to me it's always looked like they have run the project as if building a business out of it was the priority. I'm sure their recent IPO will result in much more openness... that's usually how things go, right? Nothing wrong with that, just don't be fooled into thinking they're something they're not.

To clarify, while Broadcom is a key partner for the Raspberry Pi Foundation, they don't own all the key silicon that makes it onto Raspberry Pis. For example, the "RP1" chip that is effectively a Southbridge on the Pi 5 was designed by and owned by the Raspberry Pi foundation/company, and the same is true of the chips used on Pi Pico boards. I wouldn't expect a new Pi to use all their own chips, but in theory it's possible.

Yeah, if by "all the Raspberry Pis" you mean "the Pi4 and Pi5 models".

There's nothing on the Pi1, Pi2 and Pi3 which I find a bit disappointing, as especially the different models of the Pi1 would have been interesting to compare

Jonathan Clark?

...of Crack Dot Com fame?

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