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OpenESC, AM32. Step 4 of 4

Recover a failed ESC update

Coming after bench verification: reflashing an OpenESC from the firmware page is not available yet. This page covers what you can do today: reconnect and read the ESCs, and get help. It is also for an ESC that was flashed with another tool.

A failed or interrupted ESC flash is almost always fixable. The AM32 bootloader sits in its own part of each processor's memory and is not overwritten by a firmware update. After a failed flash, that motor's processor stays in its bootloader and waits for firmware. Its motor will not spin, but the processor can be flashed again.

You need

  • A computer with Chrome or Edge
  • A USB-C data cable for the flight controller
  • Your OpenESC, connected to a flight controller running Betaflight with the 8-pin cable
  • A charged flight battery

Steps

  1. Unplug the battery. Unplug the flight battery and wait a few seconds. Leave the propellers off.
  2. Reconnect. Set up as in step 1: USB to the flight controller, then plug in the battery.

    You should see: Start-up beeps from the ESCs that still have firmware. The failed one may stay silent.

  3. Read the ESCs. Read the ESCs as in step 1 (read only), then click Disconnect.

    You should see: The failed ESC may show no firmware name, "unreadable" or an unknown version. That is expected.

  4. Reflashing: coming after bench verification. Flashing again from the firmware page is not available yet; see Install AM32 on your OpenESC. Do not flash third-party AM32 files onto the OpenESC. Leave the failed channel as it is and open a support ticket with the ESC model, the channel and what the tool showed.

    You should see: Nothing changes on the ESC. The other channels keep working.

  5. Unplug the battery. Unplug the flight battery, then the USB cable. Keep the propellers off until the ESC is sorted out.

If it doesn't work

The failed ESC is not found at all, even after a power cycle.
Check the 8-pin cable and the solder joints on that motor's signal pad, then retry.
The Betaflight app no longer connects to the flight controller.
It is still in ESC passthrough. Power-cycle the flight controller to leave passthrough: unplug USB and the battery, wait five seconds, then plug USB back in.
It still fails after several tries.
Open a support ticket with the ESC model, which motor channel fails and what the tool showed. If the bootloader itself were damaged, the processor would need a special programmer, which is not a job for a beginner.

Go to the firmware page