ESP32 Web Flasher

What it means: The computer can't see your board.

Likely causes: Charge-only cable, loose plug, missing driver.

Try this:

1. Use a different USB data cable.
2. Plug directly into the computer, not a hub.
3. Unplug, wait 5 seconds, replug.

What it means: The browser's port list is empty.

Likely causes: Unsupported browser, cable, or driver.

Try this:

1. Use desktop Chrome or Edge.
2. Check the cable and driver.
3. Close other apps that use the port.

What it means: The browser or system blocked access to the port.

Likely causes: Port used by another app, or access was denied.

Try this:

1. Close Arduino IDE and serial monitors.
2. Click Connect again and choose the port.
3. On Linux, add your user to the 'dialout' group.

What it means: The cable has power wires but no data wires.

Likely causes: Cheap or phone-charging cables.

Try this:

1. Try a cable that came with a data device.
2. Test the cable with another board.

What it means: The computer lacks the USB-serial driver.

Likely causes: Boards using CP210x or CH340 chips.

Try this:

1. Install the CP210x or CH340 driver from the chip maker.
2. Replug the board and retry.

What it means: The firmware doesn't match your chip (e.g. ESP32-S3 vs ESP32).

Likely causes: Wrong download or wrong flash address.

Try this:

1. Check the chip name shown after connecting.
2. Download firmware built for that chip.
3. Check the flash address in the firmware's docs.

What it means: The board didn't switch to flashing mode.

Likely causes: Board needs manual boot mode, weak USB power.

Try this:

1. Hold the BOOT button, click Connect, release after it starts.
2. Try another USB port or cable.
3. Tap EN/RESET once, then retry.

What it means: Writing stopped before it finished.

Likely causes: Cable unplugged, power dip, tab closed.

Try this:

1. Do not unplug during flashing.
2. Reconnect and flash again.
3. Use a short, good-quality cable.

What it means: The file is empty, too big, or in the wrong form.

Likely causes: Wrong file picked, partial download.

Try this:

1. Re-download the file.
2. Check size and the flash address.
3. Use a manifest with hashes if possible.

What it means: The write finished, but the firmware doesn't run.

Likely causes: Wrong firmware for the board, missing bootloader/partition files.

Try this:

1. Flash all required files (bootloader, partitions, app).
2. Press EN/RESET.
3. Try again with firmware made for your exact board.