Use Esp Web Tool to Recovery 2A Firmware

In rare cases, the firmware can be corrupted, which includes problems in updates, or accidentally tapping Initialize in the ESP Web Tool.

At such times, the sensor will not be able to reboot and will remain in a rebooted state.

At this point you will need to put the device into DFU mode and then re-flash a firmware.

Recognizing Firmware Corruption

In normal operation, it is extremely unlikely that natural firmware corruption will occur.This is because this is a microcontroller's job to ensure thatThis is because it is the microcontroller's responsibility to ensure the stability of theThis is because it is necessary for the microcontroller to ensure stable operationBecause this is what the microcontroller has to do to ensure stable operation of theThis is because it is a basic requirement for stable operation of a microcontroller.This is because it is a basic mechanism for the microcontroller to ensure stable operation.This is because it is one of the basic mechanisms to ensure stable operation of the microcontroller.

However, it is still possible to erase the firmware by careless operation, especially a trap: when using the ESP Web Tool to view logs or configurations, it is very easy to accidentally click the Prepare for first use Button.

A Trap in ESP Web Tools

If you doing this, then will wipes out the original sensor firmware and places the sensor in standard firmware, at which point it will not start.

Like this example: https://www.reddit.com/r/screekworkshop/comments/15rn0ok/2a_in_boot_loop_and_cant_flash_it_with_firmware/

The brick boot log looks like this(Vide By James Hodgkinson) https://www.youtube.com/watch?v=7KO_hOW1pGw

When these situations occur, the sensor is no longer working properly and you need to rewrite the firmware. Don't panic, the following process will guide you on how to do this.

Put Device Into DFU Mode

The first thing to do is to put the device into DFU mode, which will require opening the case. You need to find something relatively sharp, in our case we used a spoon.

In our production we use a professional pry bar.

When entering DFU mode:

The serial port connection can be maintained stably in the computer.
The two small red lights on the motherboard remain slightly illuminated.

Exploration continues and you can now move on to the next step, restoring the firmware.

Reflash Factory Firmware

First you need to get our Factory firmware

Direct Download

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Note that you can't use the OTA firmware because the OTA firmware is missing the Bootloader part, which will not boot. For the same reason, the factory firmware cannot be used for ota updates either, that would be equally impossible to update, it won't run, but it won't

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Factory firmware may not be the latest firmware, if the recovery is complete, you can continue to update to the new version later with the ota firmware.

Next you need to access the ESP Web Tool. https://web.esphome.io/

After connecting to the device, select Install Firmware and wait a moment for it to finish and the entire firmware reset is complete.

Here is a vide demo:

After you that, you may need to reboot the device:

If the box is open, you can press the RST button.
You can also force a reboot by re-plugging the USB power supply.

Now you'll be able to determine if it's booting up properly by going through the indicator lights, and also through the logging feature of the ESP Web Tool.

Close The Case

The final job is to combine the box back together, in this step, please check that the wires and radar module are properly homed.

When combining the box, please align the snap on the side that does not contain the USB port first, then apply slight force and finally close the USB port side.

In general, we use materials that are strong enough to keep the lid open repeatedly.