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Yes. You can build and run Zephyr firmware for supported ESP32-family targets without a physical board by using Espressif’s QEMU fork. It prints console output for workloads that use the parts of the chip the emulator models, but it cannot validate Wi-Fi, Bluetooth, or many real peripherals. The workflow below covers the documented ESP32, ESP32-S3, ESP32-C3, and ESP32-C6 targets.
What Zephyr’s ESP32 QEMU setup can—and cannot—test
Espressif’s fork adds ESP32-family machine models that are not included in the QEMU bundled with the Zephyr SDK or typical distribution packages. Install the Espressif build, rather than assuming an existing qemu-system-* binary can run ESP32 firmware. Zephyr documents QEMU board variants for ESP32, ESP32-S3, ESP32-C3, and ESP32-C6, though the available features differ by chip.
Emulation is useful for software bring-up and tests that rely on modeled functions such as boot, UART console output, flash, timers, eFuse, and selected cryptographic or other SoC blocks. It is not a substitute for checking the firmware on the physical device. Zephyr’s ESP32-DevKitC documentation describes the opt-in configuration this way: “The same firmware image can then be flashed to hardware (without that option) or run under QEMU.”
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1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsZephyr’s current per-chip documentation marks many features as unavailable in its QEMU variants, including Wi-Fi, Bluetooth, USB, general-purpose SPI, I2C, I2S, RMT, GPIO matrix/IOMUX, ADC/DAC, touch, MCPWM, pulse counter, ULP, and board GPIO keys. LEDC support is limited to ESP32; SD/MMC is not emulated on ESP32-S3. The ESP32-C6 page also lists omissions including TRNG and AES. Consult the ESP32-DevKitC and ESP32-S3-DevKitC feature tables for the target you intend to use; an application or driver test that needs an unavailable device will not run meaningfully in that variant.
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Choose the test environment that matches your question
| Environment | What runs | Best fit |
|---|---|---|
unit_testing |
Test code and the Ztest harness as a host executable; the Zephyr kernel and driver model are not built. | Isolated module logic. Provide stubs or mocks for external dependencies. |
native_sim |
The full Zephyr OS, including kernel, devicetree, drivers, and subsystems, compiled into a host binary. | Integration testing in a host environment when ESP32 SoC behavior is not the thing being tested. |
| Espressif QEMU | ESP32-target firmware running against the SoC functions modeled by the Espressif machine. | Target boot and supported core-block tests without a physical board. |
| Physical ESP32 hardware | Firmware on the actual chip and attached peripherals. | Wireless behavior and hardware, reset, or peripheral behavior outside the emulator model. |
These options make different claims about your code. A passing host unit test says nothing by itself about the ESP32 boot path; a successful QEMU boot does not establish that Wi-Fi or an unmodeled driver works on a device. Zephyr’s board documentation also notes that its simulation: metadata was not wired for Twister at the time documented, so use the board’s west build -t run flow below rather than treating this as a stock qemu_* Twister simulation.
Install the matching Espressif QEMU binary
Begin with a functioning Zephyr west workspace and Zephyr SDK that can build your selected Espressif board. Install Espressif’s QEMU fork before configuring the Zephyr build. The target architecture determines which softmmu emulator you need:
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| Targets | QEMU binary family |
|---|---|
| ESP32 and ESP32-S3 | Xtensa: qemu-system-xtensa |
| ESP32-C3 and ESP32-C6 | RISC-V: qemu-system-riscv32 |
The Xtensa and RISC-V packages are not interchangeable. If you install QEMU somewhere nonstandard or change its configured path, do so before configuring the Zephyr build; if the path changes later, rerun a pristine build so Zephyr can probe the intended binary again.
There is a version caveat for ESP32-C6. Zephyr’s cited board documentation says C6 support had been merged in Espressif’s development branch but was not included in prebuilt release esp-develop-9.2.2-20260417. In that documented state, building the Espressif esp-develop branch was necessary for C6. Check the current Zephyr board page and Espressif releases before choosing a binary, as those release facts can change.
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Build and run the Zephyr hello-world sample
For the ESP32-DevKitC QEMU board variant, from the root of a working Zephyr workspace, build and run the sample as follows:
west build -b esp32_devkitc/esp32/procpu/qemu
zephyr/samples/hello_world
-d build-qemu-esp32 --no-sysbuild --pristine
west build -d build-qemu-esp32 -t run- Build for the QEMU board qualifier. The
/qemuqualifier selects the documented emulation variant rather than the ordinary hardware configuration. - Run the generated image. The board’s emulation platform wiring provides the
runtarget; it starts the configured Espressif QEMU binary and presents the firmware’s console output in the terminal.
Another documented route is to build the hardware board name and enable QEMU with -DCONFIG_ESPRESSIF_QEMU=y after the west -- separator. This configuration creates the merged SPI flash image the emulator needs; for ESP32, the build also prepares an eFuse image. The same firmware configuration can therefore be built for emulation or, without that option, for the corresponding hardware board as described on the ESP32-DevKitC page.
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- SupportThree Modes: AP, STA, and AP+STA
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Match the flash image size to the emulator
Espressif’s QEMU tutorial states that the emulator accepts SPI flash images padded to 2, 4, 8, or 16 MB. Zephyr’s merged image follows the size of the board’s zephyr,flash device-tree node, so the selected board or overlay must specify one of those supported sizes. A mismatch can prevent the emulator from accepting the image; check the board configuration and any overlay before changing the QEMU command.
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Examples beyond hello world
Espressif’s tutorial documents more than a basic console boot. Its examples include:
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- Crypto samples and tests, plus Timer Group watchdog tests.
- Memory-layout tests using both Simple Boot and MCUboot.
- Clock-control API tests on several chips and retained-memory API tests.
- Xtensa interrupt tests.
- PSRAM tests on ESP32 and ESP32-S3 when QEMU is given a matching memory size.
These are examples of workloads documented for the emulator, not a guarantee that every Zephyr application or driver test is supported. Check whether each test’s dependencies appear in the selected SoC’s current emulation feature list.
When to move from QEMU to a board
Use QEMU while the question is about firmware startup, console output, or modeled chip blocks. Switch to a physical board when the result depends on Wi-Fi, Bluetooth, USB, a listed unmodeled peripheral, attached circuitry, or real-device behavior the emulator does not represent. QEMU removes the requirement for a board during those supported software tests; it does not remove the need for hardware validation of features beyond its model.
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