The Raspberry Pi 400 was definitely a curveball. Looking like a Raspberry Pi keyboard, inside the case was a SoC similar to the Raspberry Pi 4. And according to a device tree overlay spotted by Hackaday It seems that Raspberry Pi is working on the Raspberry Pi 500, a version based on the current flagship Raspberry Pi 5.
Over on the Raspberry Pi GitHub repository for the arm64 OS we can see arch/arm64/boot/dts/broadcom/bcm2712-rpi-500.dts, which is the first device tree overlay for the Raspberry Pi 500. And it looks like it will use the same Broadcom BCM 2712 SoC as the Raspberry Pi 5.
We can't spot any specs, but if Raspberry Pi follow the 400's spec sheet, then we should expect around 4GB of RAM, two USB 3.0 ports, a single USB 2.0, dual micro HDMI, a microSD slot, Gigabit Ethernet, and a USB type-C port for power. There should also be a GPIO breakout, which will need an additional breakout board for use with a breadboard or the best HATs.
But what about the PCIe connection for addons and M.2 SSDs? We took apart our Raspberry Pi 400, and if the PCB design for the 500 follows the 400, then there is space. It would require taking the Raspberry Pi 500 apart, but it could be easily added. We mocked up what it could look like, using a Pinedrive HatDrive Nano, the smallest M.2 breakout board that we have reviewed for the Raspberry Pi 5. This fits into the PCB, but Raspberry Pi would obviously use its own integrated connection.
What about cooling? The Raspberry Pi 5 needs active cooling. The Raspberry Pi 400 has a 1.5mm thick aluminum heatsink that reaches the full expanse of the keyboard. This is enough to keep the Raspberry Pi 400's SoC cool, a SoC that also introduced an updated 1.8 GHz CPU speed as the default. Something which could be activated on older chips. Could it keep the Raspberry Pi 500 cool? Chances are that it could for 90% of what we use a Raspberry Pi 5 for. Active cooling would be nice to have, but it would require redesigning the PCB and may impact the keyboard above it.
Finally, we have to think about camera access, or the possible lack thereof. The Raspberry Pi 400 has no means to connect any Raspberry Pi Camera. With Raspberry Pi's push towards AI in the form of the Raspberry Pi AI Camera and the AI Kit, we may see a camera port appear. But in all honesty, we really don't know.
When will the Raspberry Pi 500 be hitting the shelves? No idea. As this is the first public commit for the Raspberry Pi 500, we can guess that it is coming soon. Previous commits to a repository were probably made behind the scenes as the dev team worked with the engineers to bring the Raspberry Pi 500 to life.
How much will the Raspberry Pi 500 cost? For the Raspberry Pi 400 in 2020 we saw a $70 pricetag for just the unit. Kit prices went from $100. A Raspberry Pi 5 4GB is $60, and we can see 4GB being the sweet spot just like the 400. So $80 to $90 may be the price of the Raspberry Pi 500. We'll just have to wait and see.