CIX has finally released the technical reference manual (TRM) for the P1 (CD8180/CD8160) Arm Cortex-A720/A520 SoC, along with developer guides for the GPU (Arm Immortalis G720 and NVIDIA/AMD discrete graphics cards), the AI accelerator, as well as OS (Android, Linux, and Windows) and firmware (BIOS) installation and development.
A slow (but steady?) progress
There was a lot of excitement when the Radxa Orion O6 mini-ITX motherboard was introduced in December 2024, as we were told the CIX P1 12-core Armv9 processor would offer performance similar to Apple M1 SoC and Qualcomm 8cx Gen3 platform, at an affordable price ($199 and up for the mini-ITX board), and software support would include a Debian image, full UEFI via an open-source EDKII implementation, as well as an SDK along with hardware and software documentation, community forum support, and regular firmware & OS updates. CIX was even called “a native open source ecosystem chip company“.
So expectations were high. When I first tested the Radxa Orion O6 with Debian in March 2025, the performance was much better than other Arm platform I had reviewed like the Raspberyr Pi 5 and RK3588 SBCs, but a bit short of “Apple M1” claims, and most features worked with the provided Debian image, but it still nedded some work with disappointing GPU performance, Displayport not working, and USB ports were not compatible of my NVMe enclosures. High idle power consumption (16-17W) for an Arm platform was also an issue and has not been resolved to date.
The pace of development and documentation release was also slower than expected, so excitement gave place to disappointment and frustration among many users. Still, things were happening: the source code was first released in early March 2025 along with initial Linux upstream work, Arm SystemReady SR certification was obtained at the end of April, and more recently, the Mali GPU got better support.
A look at available documentation for the CIX P1 SoC
But documentation took way longer than expected, and we’ll now find documentation on the CIX developer website, about one year after the Orion O6 was unveiled.
To access the CIX P1 documentation, you’ll need to scroll down to the “Documentation Resources” section with Firmware, OS, AI, Graphics, and Chip Manual downloads. Click on Download does not open the file, but instead you need to register and account with email and phone number… This requires manual approval too… I already had alredy an account from my early review, so I could download the files. [Update: Only the Chip Manual (TRM) section requires registration, but you can download it from Radxa (files removed) as an alternative, so all documentation can be accessed without registering an account with CIX. Thanks to markon for the tip.]
Here’s a summary for each section.
Firmware
The firmware documentation includes two files:
- CIX-P1-Active Cooling TRM-V1.0.pdf (33 pages) – Active Cooling TRM to learn all you need about fan control for the P1
- CIX-P1-BIOS Porting Guide-V1.0.pdf (62 pages) – CIX P1 BIOS Porting Guide with chapters to set up the build environment in X86 Ubuntu, Arm Ubuntu, or Windows, port the BIOS, and a BIOS application guide
OS
The OS zip file contains seven files for Android and Linux software development, and Windows 11 installation on the P1:
- CIX-P1-Android Board Bringup Guide-V1.0.pdf (32 pages)- Android development and the Android boot process
- CIX-P1-Android OS Development Guide-V1.0.pdf (105 pages) – Overview, and chapters about fastboot, Android Debug Bridge, a building guide, recovery mode, OTA with A/B system, AVB, OPTEE secure storage, Keymint, gatekeeper, and more.
- CIX-P1-Linux ACPI Board-Level Bring-up Guide-V1.0.pdf (105 pages) – Exactly the same content “CIX-P1-Android OS Development Guide-V1.0.pdf”… Ooops.. they should probably fix that.
- CIX-P1-Linux DT Board-Level Bring-up Guide-V1.0.pdf (28 pages) – Linux development, the boot process, “adaptation instructions” for the BIO and system, and kernel adaptation (DTS, grub…).
- CIX-P1-Linux DT Development Guide-V1.0.pdf (61 pages) – Pintrctl, GPIO, PWM, Watchdog, and UART/I2C/SPI usage
- CIX-P1-Linux OS Development Guide-V1.0.pdf (54 pages) – Firmware flashing and Debian OS installation, Debian OS application usage, Debian OS development, Openkylin OS Usage, and Deepin OS Usage
- Windows 11 Installation Guide v1.1.pdf (14 pages) – Instructions to create a Windows PE boot disk on a USB drive, install the Windows ISO image on the USB drive, and install Windows 11
“~$ndows 11 Installation Guide v1.1.docx” can be ignored since it’s a corrupted file (likely the same as Windows 11 Installation Guide v1.1.pdf).
AI
We have two files for the built-in NPU and AI software development:
- CIX-P1-NOE SDK and AI ModelHub Development Guide-V1.0.pdf (47 pages) – Introduction, Neural One (NOE) SDK installation/usage, NOE Compiler, CIX AI Model Hub, and NOE quantization
- CIX-P1-NPU Development Guide-V1.0.pdf (42 pages) – Introduction, CIX NPU hardware configuration (DTS), NPU drivers for Linux and Android, NOE SDK, CIX AI Model Hub minimal description (details are in the above document), and debugging methods.
Graphics
The graphic documentation is a single 25-page file (CIX-P1-Linux GPU Development Guide-V1.0.pdf) that explains how to get started with Arm GPU driver development using the proprietary driver, as well as NVIDIA/AMD graphics cards adaptation, and a section on Panfrost/Panthod open-source driver configuration.
Chip Manual (aka TRM)
The technical reference manual for the P1 was the most requested document. It’s comprised of two files:
- CIX-P1-TRM-Part 1-V1.0-Public Developers.pdf (6179 pages) – Covers System overview, CPU, GPU, NPU, VPU, DPU, SMMU, and PCIe.
- CIX-P1-TRM-Part 2-V1.0-Public Developers.pdf (3051 pages) – Covers USB, FCH (GPIO, SPI, I2C, UART, I3C, timer, XSPI, and DMA), DDR, ISP, DP, Audio, MIPI, and Debug
All this will help if the community is interested in improving the software for the CIX P1. It’s unclear whether any of that will help fix the high idle power consumption, which is a non-starter for some people. I suspect I might require SoC-level power management optimizations that would probably have to be handled by CIX themselves, although I can see a few power management sections in the P1 TRM. In the worst case, it might require a new silicon revision.
Thanks to redefineme for the tip.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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Thanks for the article and for sharing this update.
Accessing the CIX P1 documentation remains difficult for individual and non-commercial users.
The registration process appears primarily designed for corporate or local entities, and the signup form still rejects phone numbers regardless of the format used, a problem already encountered during the early access phase.
the broad confidentiality scope prevents community sharing or referencing of the documentation, which means users who cannot complete registration have no alternative way to access information.
Given that the project was initially presented as open-source oriented, there is a clear gap between that positioning and the current access model.
This feedback is provided in the hope that it can help improve accessibility for individual and non-commercial users.
I can’t remember what I used for the registration since it’s been a while, but you may try to use a random mobile Chinese number (ask AI to generate one).
This response demonstrates a lack of discernment about the actual implications of the problem.
On one hand, the project is presented as open-source.
On the other, there was an uneven early access, documentation awaited for months, a broken registration form, workarounds that have become normalized, and a confidentiality framework that prevents any sharing or community support.
Taken individually, each of these points might be explainable.
Taken together, they create a clear gap between the stated vision and the actual experience, to the point where it becomes difficult to know where to stand.
We’ll be able to see in the BIOS docs if they indicated how the OPP are parsed since BIOS 0.3, as the format changed after 0.2.2 and they’re no longer recognized, forcing us to suffer a significant performance loss when upgrading.
Having to create an account just to download a TRM is not a good thing at all for a self-touted “opensource friendly” company…
I’m also noticing that the github repository links for edk2 and kernel at the bottom of the opensource page point to Radxa’s github repos. I don’t understand why CIX doesn’t point to their own repos. This in itself seems to be an acknowledgement for Radxa having done most of the work!
Well at least P1 is one up on Apple now. Is there even such a TRM for the Apple M1 or is that a unicorn.
Firmware, OS, AI, Graphics docs links are available without registration.
note that most of the links are in fact to Radxa’s repositories. I’m still not certain whether we have all the CPU initialization and clock setting code there, will have to dig through this.
TRM mentioned seems to also be available from radxa directly dl.radxa.com/orion/docs/
without any registration – seems to be the same as the same page counts. sadly there is no other docs there (maybe yet?) – but they are availeble from CIX directly without registration
Downloaded, thank you 🙂 There are indeed the 2 parts inside, a 85MB file and a 65MB one.
Thank you! I’ve updated the article accordingly.
So in the end, there are 5000 pages of PCIe spec, 1500 pages of USB register definitions, 1000 pages of DPU specs, 9 pages of VPU description, 5 pages of NPU description, 3 pages of CPU description and 2 pages of GPU description, and 2 pages for the DDR. The coverage is really unequal between areas. You won’t even find there anything like a CPU register or how DVFS works for example. I was initially enthousiast and much less now that I’m suspecting that we won’t have more and that we’ve been dragged into this “opensource” claim from the beginning.
At least the CPU ‘section’ references these three separate documents: cortex_a720_r0p1_trm.pdf, cortex_a520_r0p1_trm.pdf and dsu_r2p0_trm.pdf
Though no idea where to find those or if they are ever released to the public. After almost a year dealing with this platform maybe the best to do is to forget about it?
maybe it’s some TRM’s directly from ARM ? just guessing
But i’m also dissapointed as don’t see things like “absolute ratings” as in rockchip trms
But besides cix also started some mainline work it seems
At least that what they “declaring” by all this “Planning” statutes on mainline support page – https://github.com/cixtech/linux-mainline/wiki
Finally one place for tracking how its going, as collabora for r3588 did
Given all the “planning” stuff, especially for CPU idle and DVFS, we should not hope to see this platform well supported faster than any new rockchip device in the end, and people are going to see the usual 11-14W idle power consumption for a while. It will really start to work once the device is no longer relevant, as it usually happens with rockchip devices, except that these ones claimed “you will see, we’ll change everything that used to upset you with other vendors”, but did exactly the same.
Not exactly hard to find:
DSU (r2p1, not r2p0) https://documentation-service.arm.com/static/665742298ad83c4754308358
A720 https://documentation-service.arm.com/static/64a3e7fcdf6cd61d528c478f
A520 https://documentation-service.arm.com/static/6473f49916f0f201aa6b553b
The system controller, power management and sensor fusion stuff have dedicated processors (and their firmware?) to function well. All remain undocumented.
Sadly, the TRM files are gone. It appears CIX asked Radxa to remove them from their server.
We’re still extremely far from “open source friendly” stuff here… They used this lie to make a great marketing buzz, but those of us who bought boards with this chip still have to blindly rely on binary blobs. Even the format of the BIOS configuration parts that are consumed by their blobs is not documented. I could configure DVFS and DRAM speed on my BIOS version 0.2 and I can’t upgrade because the format changed later and I couldn’t figure at all how to produce equivalent entries. And I continue to have stupidly numbered CPUs… This remains a great board, but my acquisition was a bet based on a promise and I lost.