Flash Bruce firmware on the M5Stack Cardputer
Install the open-source Bruce firmware on your M5Stack Cardputer directly from this page — nothing to download or install. You need Chrome or Edge on a desktop computer and a USB-C data cable.
Important before flashing
Remove the SD card before flashing. After Bruce is installed, format the SD card, then reinsert it before first use.
How do I flash Bruce on a Cardputer?
Connect the Cardputer with a USB-C cable, click Connect above, choose the serial port, then click Flash. The Cardputer uses an ESP32-S3 and enters flash mode automatically — you do not need to hold any buttons.
Which browsers can flash the Cardputer?
| Browser | Supported |
|---|---|
| Chrome / Edge (desktop) | ✅ Yes |
| Chrome (Android) | ✅ Yes |
| Safari (macOS / iOS) | ❌ No |
| Firefox | ❌ No |
Browser flashing relies on the Web Serial API, which ships only in Chromium-based browsers.
Troubleshooting
| Symptom | Fix |
|---|---|
| No port shows in the picker | Use a USB-C data cable (not charge-only) and try a different port. |
| "Failed to connect" | Unplug and replug the device, then click Connect again. |
| Download / CORS error | The firmware host is briefly unreachable — wait and retry. |
| Wrong chip detected | Make sure no other app (Arduino IDE, serial monitor) holds the port. |
| "Module not found" after flashing | Check whether an old brucePins.conf is still present on the SD card or in the device's internal storage, and remove or replace it if needed. If the warning persists, remove and format the SD card, flash Bruce again with the one-click installer, then reinsert the card after flashing is complete. |
| Cardputer reboots unexpectedly (e.g. on RF Scan) | A Bruce 1.15 firmware bug — not a hardware fault. Flash the default 1.14 (we've reported it to the Bruce team; a fix is expected). |
What is Bruce?
Bruce is an open-source firmware tool for ESP32 devices used in wireless and hardware research and education. Source code and releases are published at github.com/BruceDevices/firmware under the AGPL-3.0 license.
Frequently asked questions
Which Bruce version should I flash on the Cardputer / Cardputer ADV?
We flash Bruce 1.14. Bruce v1.15 can reboot unexpectedly on the Cardputer (for example during RF Scan) — this is a firmware bug, not a hardware problem. We've reported it to the Bruce team and expect a fix soon, so for now we've withheld v1.15 and ship the stable 1.14. If you already installed 1.15 and hit the reboot, just re-flash here to go back to 1.14.
What is Bruce firmware?
Bruce is an open-source multi-tool firmware for ESP32 devices, with Sub-GHz, RF, infrared, RFID/NFC, WiFi and BadUSB tools in one menu. It is community firmware (AGPL-3.0); this page flashes the upstream binary.
Does the Cardputer enter flash mode automatically?
Yes. The Cardputer / Cardputer ADV use an ESP32-S3 with USB-Serial-JTAG, so the flasher resets it into the bootloader over USB automatically — just click Connect, no buttons.
Do I need an RF module for Bruce?
Bruce's Sub-GHz and 2.4 GHz tools need a CC1101 + nRF24 add-on such as the Hydra RF (Cardputer ADV) or Switchblade RF 3-in-1. Without a module the RF menus have no radio to drive.
Which browsers can flash the Cardputer?
Chrome or Edge on desktop (and Chrome on Android). Flashing uses the Web Serial API, which Safari and Firefox do not support.
WARNING
For educational and lawful testing purposes only. Comply with all applicable laws in your jurisdiction.