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How to Flash Firmware on an 8-bit ESC

6/18/25About 1 min

This guide explains how to flash firmware onto 8-bit ESCs using the online tool ESC Configurator.

It supports both classic BLHeli_S firmware and Bluejay firmware.

Note:

  1. The ESCs used on the SpeedyBee F405 V3 flight stack are 8-bit, and the factory default firmware is BLHeli_S. To use bidirectional DShot, you’ll need to flash Bluejay firmware. However, Bluejay can be picky with certain frames, potentially causing desync or twitching issues.

You can try flashing Bluejay first; if you notice twitching, simply flash back to BLHeli_S. For beginners, it's recommended to stick with the default BLHeli_S firmware to avoid bricking the ESC during flashing (e.g., due to a power interruption). Unlike 32-bit ESCs, 8-bit ESCs cannot be recovered easily once bricked — they need to be factory reflashed with specialized tools.

2.Important Warning: Do not disconnect power during the flashing process, or your ESC may become permanently bricked.

Again, 8-bit ESCs can't be recovered like 32-bit ESCs.

Firmware Flashing Steps

  1. Remove the propellers.
  2. Power on the quadcopter. The ESC must be powered via the battery to be recognized by the ground station.
  3. Ensure ESC protocol is configured in Betaflight. The default is DShot600. Without this, ESC Configurator will not detect your ESCs.

4.Open the ESC Configurator in your browser: https://esc-configurator.com/

5.Follow the step-by-step instructions as shown below. Pay special attention to Step ⑥, where you must select the correct ESC type (e.g., J-H-40, J-H-50, etc.).

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⚠️ Critical Notes on Step ⑥:

  1. Make sure you select the correct ESC type. This is specific to the brand/model and usually listed in the product manual. For SpeedyBee F405 V3 Stack (50A ESC): select J-H-50 For SpeedyBee F745 AIO 35A, SpeedyBee F7 Mini, or F4 Mini with 35A ESC: select J-H-40
  2. If flashing Bluejay firmware: Select J-H-50 Start with the default firmware version v0.17.0 Set PWM Frequency to 24KHz initially (Higher isn't always better — it depends on your motors and overall setup.)

PWM tuning tips: Start with 24kHz. After a flight, check motor temperature immediately by touch. If motors are not too hot (your finger can stay on them comfortably), you may try increasing to 48kHz and test again. 96kHz is not recommended unless you're sure your setup supports it.

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