Fnirsi | Dso-tc2 Firmware

As of 2025, the DSO-TC2 is still in production, but FNIRSI has released newer models (DSO-TC3, DSO-TC4 with color displays). However, the TC2 has a massive user base. FNIRSI continues to release firmware updates about twice a year, mostly small fixes.

The community is now the main driver of improvements. If you rely on the DSO-TC2 professionally, consider joining the Facebook group or EEVblog thread for the latest beta firmware.

The SPI flash is not protected either. Using a Bus Pirate or dedicated programmer: fnirsi dso-tc2 firmware

Contents: Framebuffer tiles, calibration tables, and strings.

The firmware’s UI is where the DSO-TC2 shows its consumer-facing polish. The 2.8-inch 320×240 IPS display is bright and legible, and the firmware uses large icons and simple menus. Navigation is via four buttons and an encoder wheel—a common control scheme for pocket scopes. As of 2025, the DSO-TC2 is still in

Yet, the firmware’s UX has several quirks:

The firmware does, however, include a few thoughtful touches: a battery voltage indicator, a screenshot capture function (saving to a BMP file), and a simple waveform generator (using the same probe as an output). These features suggest that the developers did listen to user feedback, but only within the constraints of an already-finished firmware architecture. Contents: Framebuffer tiles, calibration tables, and strings

To understand the DSO-TC2’s firmware, one must first acknowledge its ancestry. The component tester functionality is clearly derived from the famous open-source AVR-Transistortester project by Markus Frejek and Karl-Heinz Kübbeler. This project, originally designed for 8-bit AVR microcontrollers, provides automatic identification and characterization of resistors, capacitors, diodes, transistors, and even thyristors. Fnirsi’s engineers ported this logic to the STM32 platform, wrapping it in a more modern graphical interface.

This open-source foundation explains both the strengths and weaknesses of the tester side. The firmware reliably identifies thousands of components, measures parameters like hFE (transistor gain) and Vf (diode forward voltage), and displays pinouts—all within seconds. However, the legacy code also introduces peculiarities: the tester can be confused by very low-value resistors or high-capacitance capacitors, and it occasionally misidentifies complex components like JFETs. The firmware does not improve upon the open-source algorithms; it merely repackages them. In this sense, the DSO-TC2’s firmware is a compilation rather than a creation—a pragmatic choice that keeps development costs near zero.

Updating the DSO-TC2 is surprisingly simple, but FNIRSI’s documentation is scattered. Here is the only reliable method as of 2025.