Bench notes · ESP32 · MicroPython

ESP32-C5: finally, an ESP32 that speaks 5 GHz

Every ESP32 most of us have used lives on the crowded 2.4 GHz band. The ESP32-C5 is Espressif's first chip with dual-band Wi-Fi 6, so your projects can hop onto 5 GHz, which is usually far quieter.

MicroPython v1.29.0 (24 August 2026) is the release that makes it properly usable: the generic C5 firmware now handles PSRAM, and Seeed's XIAO ESP32C5 gets its own board definition.

The one thing that trips everyone up

The C5 firmware flashes to 0x2000, not 0x1000 like the original ESP32 or 0x0 like the S3, C3 and C6. Get it wrong and the board simply won't boot. Thonny bundles esptool, so you can flash it from Tools → Open system shell… without installing anything else.

Seeing both bands

A Wi-Fi scan in MicroPython returns each network's channel. Channels 1–14 are 2.4 GHz and anything above is 5 GHz, so a short script can sort your neighbourhood by band. On my bench, 2.4 GHz channels 1, 6 and 11 were packed and 5 GHz was nearly empty. Run the same script on an older ESP32 and you'll only ever see 2.4 GHz.

One trade-off: 5 GHz doesn't go through walls as well. For a sensor in the back shed, 2.4 GHz may still win.

Links: C5 firmware · v1.29.0 release notes · Thonny · wifi_band_scan.py