[Updated: Jun. 19] — Radxa unveiled a tiny, $10 and up “Rock Pi S” SBC that runs Linux on a quad -A35 RK3308. There’s also a v1.4 update of the RK3399-based Rock Pi 4 that adds 4MB SPI for booting NVMe drives plus a Rock Pi PoE HAT and a USB 3.0 eMMC adapter.



Radxa, which returned from a long development hiatus last fall with an impressively low-cost, $39 and up Rock Pi 4 SBC equipped with a Rockchip RK3399, has now returned with an updated v1.4 model with NVMe support. The email announcement from Radxa project leader Tom Cubie also previewed a tiny Rock Pi S board for voice applications, a Rock Pi PoE HAT for adding Power-over-Ethernet to the Rock Pi 4, and a USB 3.0 based eMMC reader.



Rock Pi S

Radxa has yet to post full specs or a shopping page for the Rock Pi S, which is now sampling and available for evaluation. The SBC will start at $9.90 with 256MB RAM. Presumably, this will be an open-spec community backed board like the Rock Pi 4. Aimed at IoT and audio applications, the headless SBC measures only 38 x 38mm.







Rock Pi S

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So far, Radxa has tested Debian and Buildroot on the device, which is equipped with the new Rockchip RK3308 system-on-chip. The RK3308, which is also appearing on a new Hangzhou Wild Chip Mcuzone MDK3308 Coreboard module and dev kit, features 4x low-power, 64-bit Cortex-A35 cores. On the Mcuzone module, they’re clocked to 1.3GHz. There is no 2D or 3D GPU, but the extensive audio interfaces include I2S, PCM, TDM, PDM, SPDIF, and HDMI ARC.

The Rock Pi S offers a choice of 256MB or 512MB RAM (1178Mbps) plus a microSD slot and “1/2/4/8Gbit” of optional NAND flash. You get USB 2.0 host and USB 2.0 OTG Type-C ports, as well as well as 802.11b/g/n WiFi and Bluetooth 4.0 with an external antenna.

There’s also a 10/100 Ethernet port with optional PoE. Radxa says that “additional HAT required,” but it’s unclear if it can use the new Rock Pi 4 HAT described below. Whereas the Rock Pi 4 has a 40-pin GPIO header, the Rock Pi S is limited to a 26-pin header, as well as a separate 26-pin audio header.



Rock Pi 4 v1.4

The updated Rock Pi 4 v.14 appears to be available now for the usual $39 (1GB) or $74.95 (4GB with WiFi/BT) price, as detailed in our recent catalog of 125 Linux hacker boards. The major improvement to the SBC, which is still the most affordable RK3399-based board around, is support for high-speed NVMe SSD storage via its M.2 socket.







Rock Pi 4 v.14 (left) and USB3 EMMC Reader

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Although NVMe support was listed in the original Rock Pi 4 announcement , it apparently was not supported until now. A new allotment of soldered 4MB SPI enables booting from NVMe.

“We have reduced the size of the image so 4MB flash can just include the first stage loader, u-boot and trust image,” notes Cubie. “We ported the RK3399 PCIe driver to u-boot and enabled the boot chain. Android is also supported for NVMe booting, which will come in later release.”

The Rock Pi v.14 is further enhanced with external antenna support for the WiFi radio on the 4GB Model B, and the headphone connector has been improved with “through hole legs for strengthened mounting.” Other minor changes include the user LED changing from red to blue and “changes the USB3 OTG label to simple L/H for Host/Device.”

The Rock Pi 4 closely matches the Raspberry Pi layout and feature set, but offers the much faster, hexa-core Rockchip RK3399. It’s equipped with a native GbE port, a pair each of USB 3.0 and 2.0 ports, and a 4K-ready HDMI 2.0 port in addition to 2-lane MIPI-DSI and -CSI. Other features include an audio jack with mic, an RTC, and a USB Type-C port for power. The SBC has a 0 to 80°C range, a 5.5-20V input, and support for Android 9.0. Debian, and Ubuntu Server.



Rock Pi Poe HAT

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Although the Rock Pi 4 was announced with support for the Raspberry Pi PoE HAT, Radxa has designed its own that is better optimized for the SBC. This is the first commercial version of the Rock Pi Poe HAT, and has been “completely redesigned” from the prototype. Compared to that model, the new version “looks cleaner by hiding the big transistor in the bottom,” writes Cubie. In addition, it adds an “optimized circuit” and a fan that enables to the device to “drop from the peak 100°C to now below 40°C.”







Rock Pi Poe HAT with (left) and without Rock Pi 4 SBC

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The Rock Pi Poe HAT is compatible with both the Rock Pi 4 and the Raspberry Pi 3B+ and offers an optional 40-pin GPIO for pass through. The board has a 5V output on the GPIO power pin.

The fan is controlled by PWM at up to 12000RPM, and is accompanied by a temperature sensor. A Debian package can automatically adjust the fan speed.



USB3 eMMC reader

Finally, Radxa unveiled a USB 3.0 form factor eMMC reader “designed for ourselves and the developers who need to write images on eMMC module frequently,” writes Cubie. The USB3 eMMC reader runs off a USB 3.1 Gen2 controller. It supports Rock Pi eMMC modules up to 128GB and is compatible with Odroid and Pine64 eMMC modules. The reader supports dual mounting as well as eMMC HS400 mode.



Rock Pi 4 Cluster Set

Some other accessories now offered on the Allnet China Rock Pi page include a $14.40 Rock Pi 4 Prototyping HAT and a $49.90 Rock Pi 4 Cluster Set. The latter includes an M.2 extension board and 4x heatsinks, as well as assembly items.



Further information

The Rock Pi S is available in limited sampling quantities with 256MB RAM for $9.90. There’s also an unpriced 512MB version. The Rock Pi 4 v.14 appears to be available now for the usual $39 (1GB) to or $74.95 (4GB with WiFi/BT) price.

There’s an Allnet China shopping page for the “sold out” and “coming soon” Rock Pi 4B Poe HAT, but no price is listed. Allnet China also suggests the USB3 eMMC Reader is coming soon, but there was no price. Radxa products are also available in Europe at Innet24.

More information and open source resources should soon appear at the Radxa website.