USB Mainboard Specs, Size and Legacy Gadgeteer Review

USB mainboard remains the smallest Gadgeteer mainboard at 57x32 mm, with STM32F407 specs and ended 2017 support.

USB mainboard from Mountaineer suits builders who want the smallest Gadgeteer mainboard core for USB-powered C# prototypes, measuring 57 x 32 mm according to the Mountaineer specification PDF accessed in November 2026. It runs an STM32F407 at 168 MHz with 1 MB on-chip Flash plus 8 MB on-board Flash and 192 KB RAM according to the same November 2026 specification. Mountaineer Group said in May 2012 that the board is USB-powered with several megabytes of onboard Flash for data logging. Support ended in December 2017 according to Mountaineer Group News, so buyers should treat remaining units as legacy hardware as of November 2026.

What Does the USB Mainboard Offer for Gadgeteer Prototyping?

USB Mainboard provides a USB-powered Gadgeteer core with 10-pin sockets for solderless C# modules.

The Mountaineer Group said in May 2012 on its News page that “The Mountaineer USB Mainboard is the smallest Gadgeteer mainboard so far.” Gadgeteer modules use physically identical 10-pin connectors and run C# under Visual Studio with .NET Micro Framework according to the Mountaineer Platform page accessed in November 2026. Our testing method checks board size, socket compatibility, and documented memory before recommending legacy cores.

The board targets minimal modular systems. Mountaineer Group said in May 2012 that USB power and several megabytes of onboard Flash support data logging.

How Do USB Mainboard Specs Compare on Size and Memory?

USB Mainboard measures 57 x 32 mm with 1 MB plus 8 MB Flash.

It runs an STM32F407 at 168 MHz with 192 KB RAM according to the Mountaineer specification PDF accessed in November 2026. The same November 2026 specification lists RoHS compliance with 0-70C operating range. The related Ethernet mainboard adds wired networking for Internet of Things prototypes with a larger 57 x 42 mm footprint according to the Mountaineer specification PDF accessed in November 2026.

Feature	USB Mainboard	Ethernet Mainboard
Board size	57 x 32 mm	57 x 42 mm
Processor	STM32F407, 168 MHz	STM32F407, 168 MHz
Flash	1 MB on-chip + 8 MB on-board	1 MB on-chip + 8 MB on-board
RAM	192 KB	192 KB
Network and power	USB powered, no Ethernet	USB powered, with Ethernet
Listed price as of November 2026	EUR 53.88	EUR 67.00

Prices above come from the .NET Micro Framework e-shop catalogue accessed in November 2026, with VAT-inclusive figures of EUR 65.19 and EUR 81.07. Table specifications come from Mountaineer specification PDFs accessed in November 2026.

Is the USB Mainboard Still Usable After 2017 Support End?

USB Mainboard remains usable as legacy hardware after December 2017 support end.

Mountaineer Group said in December 2017 on its News page that support was discontinued after Microsoft stopped further NETMF work. The group refocused on Mono on Linux for embedded C# according to the same December 2017 notice. Existing firmware, Visual Studio tooling, and C# drivers continue to function on installed boards. A gyro module illustrates the type of solderless Gadgeteer peripheral that these mainboards were designed to host.

Buyers find no public data on new-unit stock as of November 2026. Electronics Datasheets listed the USB Mainboard as out of stock when accessed in November 2026. Secondhand buyers should confirm socket condition and firmware version before paying.

USB Mainboard FAQ

What is the USB Mainboard best for?

USB Mainboard fits small USB-powered Gadgeteer prototypes that need C# and Visual Studio with solderless 10-pin modules. It measures 57 x 32 mm and runs an STM32F407 at 168 MHz according to the Mountaineer specification PDF accessed in November 2026. Current new-unit stock has no public data as of November 2026, so buyers should verify secondhand condition before purchase.

How much memory does the USB Mainboard provide?

USB Mainboard provides 1 MB on-chip Flash plus 8 MB on-board Flash and 192 KB RAM according to the Mountaineer specification PDF accessed in November 2026. That on-board Flash supports data logging without extra boards according to Mountaineer Group News from May 2012. It does not add Ethernet, unlike the Ethernet mainboard variant.

Is the USB Mainboard still usable today?

USB Mainboard is legacy hardware after Mountaineer Group ended support in December 2017 according to Mountaineer Group News. It still suits existing .NET Micro Framework codebases and spare-part repairs. Buyers should not plan new commercial designs around it as of November 2026 because firmware and retail availability have no public updates.