rpi-open-firmware

Comment by the developer who attempted to create open firmware for RPi, https://github.com/christinaa/rpi-open-firmware/issues/37 > a lot of corners were cut to save time leading to what I believe is poor ARMv7+ Cortex IP integration (GIC, TrustZone, etc). So I stopped working on it. If those things were not the case (GIC working, "TZPCs" working, security working as intended, instead of NS forced to high on bridge, at least in my understanding) I would still work on it ... ARM isn't a second class citizen on this platform, it's a third class citizen since BCM2709 (again this is an opinion) ... the features I wanted to tinker with the most are absent by design (cutting corners) and I'm not willing to resort to SW emulation of them through clever uses of the VPU. Hopefully RPi 5 silicon offers a better foundation for open firmware.

Sure, and it's been done: https://github.com/christinaa/rpi-open-firmware - but that doesn't involve ThreadX source, just some standard reverse engineering work. ThreadX is really the least interesting part of this whole operation in terms of the Raspberry Pi. It's very cool that ThreadX has been open sourced as it offers an additional battle tested and mature alternative to FreeRTOS for new projects. If they're able to get and maintain the various safety certifications for ThreadX under the Eclipse foundation, this could be game-changing in a very different space from the Pi. But in terms of reverse engineering or open sourcing the Raspberry Pi VideoCore blob, open source ThreadX is pretty much a non-event IMO.

I guess you are thinking of this issue: https://github.com/christinaa/rpi-open-firmware/issues/37 Since then the project moved to a new maintainer (not me), who worked on it slowly but surely. They need new contributors though.

> no clue if there's a project to reimplement that There was! And it even booted Linux in some capacity: https://github.com/christinaa/rpi-open-firmware > every chip is very different from one another Eh, the usual embedded SoCs are not that different from each other — ARM GIC, ARM timer, lots of Synopsys Designware crap for SDMMC/XHCI/PCIe/etc. For many SoCs it's totally feasible to make standards-compliant firmware, e.g. for the Rockchip RK3566 there is https://github.com/jaredmcneill/quartz64_uefi And SoCs from the networking world (Marvell, NXP) are typically supported by upstream EDK2.

from 2018: Is this project dead? KB - No not dead but on hold, see my response · Issue #37 https://github.com/christinaa/rpi-open-firmware/issues/37

No. If I understand correctly, we now know that the Raspberry Pi 3 can never be fully secured due to corners cut by Broadcom. https://github.com/christinaa/rpi-open-firmware/issues/37#is...

I believe the main blob is loaded from the SD card and boots the GPU, which then starts the CPU and loads the OS (the Pi architecture is weird), although I suppose there must be some tiny blob on a chip on the actual Pi board to load that stage from the SD card. There's an attempt to make an replacement for the part on the SD card: https://github.com/christinaa/rpi-open-firmware

It's been reverse engineered and some minimal firmware for the VideoCore part was made: https://github.com/christinaa/rpi-open-firmware

> It's not too far fetched, they're not very different at all, they're both quad-core A53 (ARMv8) 64-bit based SOCs with similar clock speeds, and the some of the Pine boards with more RAM can run Win10. There's a lot more to a system than the CPU. For the Raspberry Pi, someone bothered to port EDK2 and write ACPI tables: https://github.com/andreiw/RaspberryPiPkg And Microsoft themselves were interested in the Pi (for IoT Core), so they even have some support for weird Broadcom hardware in the NT kernel. If someone writes ACPI tables for Allwinner SoCs, it will work :) > more closed than RPi due to the AllWinner SOCs they use Allwinner has the most community support out of all SoCs there are. It is reverse engineered of course, but it's really good. To the point of someone writing a FOSS driver for the video decoder: https://linux-sunxi.o

Seems that the hardware is capable of sleep mode.. however the devs are not supporting it in their closed source firmware. Grr. https://github.com/raspberrypi/linux/issues/1281 Sadly the open source alternative is lacking the human resource to replace it. https://github.com/christinaa/rpi-open-firmware

Current RISC-V chips are still proprietary, it's only the ISA that is free. As for firmware, that's already pretty open with ARM. You can boot a Tegra X1 (Google Pixel C, Nintendo Switch) without any blobs with coreboot. (You still want one tiny blob — DDR4 training stuff — if you want your RAM not to be super slow.) Allwinner and Rockchip platforms also tend to not have blobs, at least not user visible/modifiable ones. You can even boot a Raspberry Pi without blobs https://github.com/christinaa/rpi-open-firmware (but without usb/ethernet/etc.)

The Pi Zero can do this as a USB client device for a host PC, including the QRCodes with the Pi camera, buttons/switches, and a small touchscreen for host-isolated verification and pin entry. Beaglebone Black (possibly also Pocket Beagle) can do it too, and the am335x does have some minimal crypto acceleration. They're not high performance, they aren't "security focused" hardware, nor are they perfect fit for the task, but they're reasonably well understood and broadly available. The Pi Zero does have a closed "GPU" firmware, but there is an effort[1] to run open firmware on it. However if you expect the host to attack the device, USB OTG (i.e. Linux USB gadget drivers) may not be a good choice, you may want to access it via network instead and that opens up more choices (though most will not be as small). The other alternatives are basi

Yep the proprietary bootloader on the Raspberry Pi handles most initialisation leaving the SoC in a usable state. If you want to see how things like DRAM init work you can take a look at the open source reverse engineered firmware at https://github.com/christinaa/rpi-open-firmware . It isn't complete but it is just about enough to also boot the Linux kernel.

> "The RPi isn't anywhere close to open hardware?" The RPi is the one of the most open of all the SBC (Single Board Computers) currently on the market: https://anholt.github.io/twivc4/ https://github.com/christinaa/rpi-open-firmware What that says about other SBC, I'll leave up to you to decide.

> a lot of those ARM SoC's have proprietary code running on their bootloader too Usually possible to replace that blob! e.g. https://github.com/christinaa/rpi-open-firmware for the Raspberry Pi