This contains my attempts at reverse-engineering the RP3A0 SoC from the Raspberry Pi Zero 2W so I can place it on my own PCB.
I plan to eventually use this in another project, but for now I need a proof of concept. I decided to make the most cursed thing I could think of, Pi Pico sized board, but with a full Raspberry Pi processor on it. It has basically the same pinout as a Pi Pico, all the GPIOs that match up are in the same position. HDMI is sketchy, there's no Wi-Fi, and USB-C is a bit weird, but it boots and I can get it online. Check the breakout/rp3a0_mini dir for this.
docs- The pinout of the RP3A0 SoC, and how I reverse engineered itdocs/reballing- How to harvest the RP3A0 from a Raspberry Pi Zero 2W and prepare it for soldering onto a PCBbreakout/rp3a0_minicontains an Altium project for the RP3A0 Pico, a carrier board in almost the same form factor as the Pi Picolibrarycontains an Altium library with the SoC footprint and the outline of the castellated pads for a Pi Pico
This was a stupid idea and you probably shouldn't do it. There are heaps of other Linux SoCs you can use, an especially ones that aren't a 21x21 BGA device with no public documentation. It's also not super easy to solder, so you might trash a couple parts trying to get it right.
- My coworkers for putting up with me asking questions about BGA reballing and PCB design
- Jeff Geerling (YouTube, website) for:
- his blog post with an X-Ray of the Pi Zero 2W that inspired this project
- being cool when I ambushed him at Open Sauce 2025 to show him my crazy project
- being the first person to test out my prototype board, giving me feedback and providing some great photos for me to use
- Raspberry Pi for making such a great little SoC, and at least releasing some schematics for it