Install the firmware

What you need

Part	Notes
Waveshare ESP32-P4-NANO (wiki)	The board this firmware is built and tested on. Its main chip, an ESP32-P4, talks to the pedal through the USB-A port. A second chip on the board, an ESP32-C6, does the Wi-Fi. Waveshare sells it in several kits. Order the Basic Kit (the board and a speaker). The box does not use the camera, PoE or display kits.
A USB-C cable that carries data	For power and flashing. A charge-only cable will not show a serial device.
A USB-C power source	A 5 V phone charger or a computer port.
The pedal's USB cable	The cable you use to connect the pedal to a computer. The end that goes into the box must be USB-A, because that is the box's pedal port. Check what your cable has on that end.
A case (optional)	A 3D-printable lid and bottom, in a single-colour and a multi-colour version. Not test-printed yet.

So far it has been tried with a Helix LT and an HX Stomp. Other Helix and HX pedals have not been tried. The Wi-Fi is 2.4 GHz only, so the setup page does not list 5 GHz networks. Other ESP32-P4 boards are untested.

You also need Helrig on your computer. Connecting to a pedal needs Helrig Connect or Helrig Pro.

Flash it from your browser

Use desktop Chrome or Edge (Windows, macOS or Linux). Safari, Firefox and phones cannot do this.
Connect the board's UART USB-C port to your computer. The pedal does not need to be plugged in yet.
Open the web flasher: https://box.helrig.com/flash
Press Install and choose USB Single Serial in the list. It may show up as usbmodem, ttyACM or a COM port.
Wait about 2 minutes and keep the tab open and the cable connected. The board restarts by itself.

Installing over a box you already set up keeps its Wi-Fi networks and pairings, so you can update without setting it up again. To wipe those too, open Options on the flasher page and tick Start as a new box before you press Install. Every device then has to pair again.

Then continue with Setting up a Helrig Box.

Drivers

None to install. The board shows up as a standard USB serial device. Seen on a macOS Mac, a Windows 11 VM and an Ubuntu VM:

System	What happened
macOS	A `/dev/cu.usbmodem...` port from Apple's own driver.
Windows 11	"USB Serial Device (COM3)" from Microsoft's own `usbser` driver. Other Windows versions are untested.
Linux (Ubuntu)	`/dev/ttyACM0` from the kernel's `cdc_acm` module.

Linux: your user must be allowed to open the port, which usually means the dialout group. Run this, then log out and back in:

sudo usermod -aG dialout $USER

Troubleshooting

The page cannot connect. Unplug and replug the board. If that does not help, hold BOOT, tap RESET, release BOOT, then press Install again. Close any other program that is using the board's serial port.
No port in the list. Try another cable (it must carry data). Check you are using the board's UART USB-C port, not the USB-A one.
"Permission denied" on Linux. See the dialout step above.
The page says the browser cannot flash. Use desktop Chrome or Edge.
The setup network does not appear. Wait about 10 seconds after power-up. Phones can also keep an old list for a few minutes.
The box stopped halfway. Run the page again. If the box still does not start, build and flash it from source.
Helrig does not find the pedal. Replug the pedal's USB cable and try again. If it is still stuck, unplug the pedal's 9 V power for a moment. A USB replug is sometimes not enough. Helrig never sends a USB reset.
Helrig says the box needs pairing, or there is no Pair button. Update Helrig to 1.5.3 or later. Then press Pair and, within 30 seconds, press BOOT on the board once. Hold it for 5 seconds and you factory-reset the box instead.
Do not hold BOOT while the board powers up. That starts the chip's download mode instead of the firmware.