[1] FNIRSI. (2022). DSO-TC2 User Manual.
[2] STMicroelectronics. (2019). STM32F405/415 Reference Manual.
[3] Winbond. (2018). W25Q16JV Datasheet.
[4] Reverse Engineering STM32 Firmware, Embedded Lab, 2021.
[5] “FNIRSI DSO-TC2 Teardown,” EEVblog Forum, 2023.
Note: This paper is a template. Actual addresses, offsets, and exact MCU variant depend on your specific DSO-TC2 hardware revision. Always verify before attempting reflashing.
I just installed the latest firmware for the FNIRSI DSO‑TC2 and here’s a quick rundown for anyone thinking of updating.
What’s improved
What to check before updating
How to update (concise steps)
Troubleshooting
Short opinion Worth updating if you rely on the scope for hobby electronics or bench troubleshooting — the UI and stability improvements feel tangible. Proceed cautiously: follow the model check and backup steps.
If you want, I can:
The FNIRSI DSO-TC2 firmware can be updated by connecting the device to a Windows computer (version 10 or above), which recognizes it as a virtual USB drive where the update file can be dropped. Firmware files and official update tools are typically available through the FNIRSI Software Download Center. Update Procedure The DSO-TC2
features two distinct upgrade modes depending on whether you are updating the oscilloscope or the transistor tester component: Oscilloscope Upgrade (CH Mode): fnirsi dso-tc2 firmware
Connect the device to your PC via a Type-C data cable while it is powered off.
Turn on the instrument and wait about 2 seconds for a disk named "CH BOOT" to appear on your computer.
Copy the firmware file (starting with "CH") into this disk. An "Update completed" message will appear on the device screen once finished. Transistor Tester Upgrade (MM Mode): Connect the powered-off device to your PC.
Press and hold the down arrow key, then power on the device.
A disk named "MM BOOT" should appear. Copy the firmware file (starting with "MM") into this disk to complete the process. Key Considerations
System Requirements: The update process requires a Windows 10 or later operating system.
Cable Quality: Ensure you use a high-quality Type-C data cable capable of data transfer (D+ and D- pins), as some charging-only cables will not trigger the boot disk mode.
Manual Reference: For detailed diagrams and specific button layouts, you can refer to the digital DSO-TC2 User Manual.
Are you currently facing a specific error message or hardware issue that you're hoping a firmware update will fix?
Updating the firmware on the FNIRSI DSO-TC2 is a common way to improve its 2.5MS/s sampling rate stability and fix component testing inaccuracies [1] FNIRSI
. While the TC2 is a legacy model compared to the newer TC3 and TC4, firmware support is still available via the official FNIRSI Download Center Firmware Update Overview
The DSO-TC2 uses a standard USB interface for firmware flashing, typically requiring a Windows PC. Official Downloads : Firmware files and PC software tools are hosted on the FNIRSI Software Page Version History
: Latest official versions (such as v1.0.6 or higher) generally focus on refining the transistor tester logic and UI responsiveness in oscilloscope mode Hardware Variants
: Be cautious; some units may use different internal MCUs (like STM32 clones). Always verify the hardware ID in the device's "System Settings" or "About" menu before flashing. How to Update
While exact button combinations can vary by production batch, the general procedure for FNIRSI multifunction testers is: Enter Upgrade Mode : Power off the device. Press and hold the
button while connecting it to your PC via a USB Type-C cable. Recognition
: The device should appear as a removable "U-disk" or a virtual COM port on your computer. Drag & Drop : If it appears as a drive, simply copy the firmware file into the root folder. : If it appears as a COM port, use the FNIRSI PC Software to select the port and "Start Upgrade".
: Once the progress bar finishes, disconnect and restart the device to apply changes. Troubleshooting Common Issues
Independent developers on EEVblog Forum and GitHub have reverse-engineered the bootloader. They offer modified firmwares that unlock:
Risks: Community firmware voids your warranty and has a higher risk of bricking. Use only if you are comfortable with JTAG recovery. Note: This paper is a template
Where the component tester excels, the oscilloscope firmware reveals the device’s cost-cutting nature. The DSO-TC2 is marketed as a 2.5 MHz analog bandwidth scope with a 10 MSa/s sampling rate—adequate for audio frequencies and basic microcontroller debugging (e.g., checking PWM signals or I2C clock lines). The firmware manages the STM32’s ADC (analog-to-digital converter) and DMA (direct memory access) to capture waveforms, then renders them on the display.
However, the firmware’s limitations become apparent upon deeper use:
These are not hardware limitations alone; they are deliberate firmware simplifications. The STM32F103 (or similar) inside the DSO-TC2 has enough power to implement basic digital triggering and averaging, but Fnirsi chose not to invest in the firmware development. Instead, the oscilloscope mode feels like a proof-of-concept—enough to claim “oscilloscope” on the box, but not enough for serious debugging.
The FNIRSI DSO-TC2 firmware is the soul of the device. Whether you’re fixing a glitch, adding new measurement capabilities, or recovering a bricked unit, knowing how to find, verify, and install firmware updates is an essential skill for any owner.
Key takeaways:
With the right firmware, the little DSO-TC2 transforms from a toy into a surprisingly capable field toolkit. Keep it updated, and it will serve you for years.
Have you successfully updated your DSO-TC2? Share your version number and experience in the comments below. For urgent brick recovery, visit the EEVblog forum thread #FNIRSI-DSO-TC2.
The FNIRSI DSO-TC2 is a popular, low-cost handheld oscilloscope and transistor tester. Because it is a budget device often subjected to software bugs or hardware revisions, firmware is a major topic of discussion among users.
Here is a helpful guide covering everything you need to know about the FNIRSI DSO-TC2 firmware, including how to update it, where to find custom versions, and troubleshooting tips.
The internal firmware starts with the STM32 vector table at 0x08000000. The reset handler points to code that initializes clocks, then configures GPIO for the frontend.
Strings extracted (strings internal_firmware.bin):
DSO-TC2 V1.2
CALIB_DATA
TP_LOW=150
TP_HIGH=2750
Component Tester Mode
ADC overflow