This tutorial targets an RPM data reading bug for BLHeli32 32.80: Wrong RPMs reduce RPM Filter effectiveness and may manifest as increased noise or low throttle twitching. The video demonstration uses the latest version of BLHeliSuite32 at the time, downloads the complete ZIP from the official GitHub repository, extracts the correct HEX in the REV32.8.1 branch, and then flashes 32.81 to the ESC matching the target one by one. As this is a historical fix process for 2021, 32.81 should not be considered the default recommended version today; current ESC targets, vendor releases and recovery plans must still be checked.
Why 32.80 needs an update
The official description and video explain that BLHeli32 32.80 introduced inaccurate RPM readings. Betaflight’s RPM Filter uses speed data returned by the ESCs to locate motor harmonics. Inaccurate data shifts the filter away from its intended target, reducing noise-control effectiveness. Twitching at low throttle is only one possible symptom, not a sufficient diagnostic criterion on its own.
To investigate, check the ESC firmware version, bidirectional DShot / RPM Telemetry status, and Blackbox data together. Do not attribute all noise to 32.80: mechanical damage, motors, propellers, flight-controller mounting, and filter configuration can produce similar symptoms.
Prepare the correct tools and firmware sources
The video emphasizes using the latest BLHeliSuite32 available at the time; older versions cannot complete this procedure. The displayed version numbers for Windows downloads were confusing then, so the author used the latest release in the official repository. After downloading, extract the package and launch the BLHeliSuite32 Windows interface.
For the 32.81 HEX, the author advises against copying individual files from a webpage or saving them separately, because text conversion can insert characters and damage the firmware. A safer method is to use Code → Download ZIP in the official GitHub repository to download the complete repository, then extract the original HEX from the corresponding REV32.8.1 directory.
Read the ESCs and flash the local HEX one at a time
Remove every propeller, connect the flight controller to the computer by USB, and power the aircraft as required by the ESC tool. Once connected, read all four ESCs first and record each hardware target and original version. The global batch-flashing list in the video did not show 32.81, so the author used the individual ESC Flash procedure instead.
If the required target is absent from the version list, choose to ignore the online list, then locate the local HEX extracted from the official ZIP. The tool attempts to match firmware by ESC name, but you must still verify the target manually before choosing Yes to start flashing. Complete and recheck each of the four ESCs individually; one successful flash does not mean the remaining targets are identical.
Verify the result and prepare for rollback
After flashing, read the ESCs again, confirm that every channel shows the expected version, and check whether the original settings were retained. With the propellers still removed, perform a brief motor test to verify consistent starting, plausible RPM Telemetry, and no abnormal heating or errors. Only then conduct a controlled test flight and compare Blackbox logs.
Flashing local or custom firmware makes target-selection mistakes more likely than choosing a stable release within the tool. Keep the original firmware, screenshots of the settings, and a recovery method. If official channels now offer a newer version, read the latest fix notes first rather than downgrading to 32.81 merely to reproduce the video.
Operation steps
- Check whether you are using 32.80
Read every ESC version and use RPM Telemetry, noise, and low-throttle abnormalities to judge whether the known issue may be involved.
- Download the latest BLHeliSuite32 available at the time
Obtain the configurator from an official source, avoiding the older versions that the video confirms cannot complete this procedure.
- Remove the propellers, connect, and read the ESCs
Remove all propellers, connect the flight controller, power it as required by the tool, and record each ESC target and version.
- Switch to flashing individual ESCs
If 32.81 is missing from the batch list, enter the Flash procedure separately for each ESC. Do not guess the target.
- Download the complete ZIP from the official repository
Download the complete repository and extract the corresponding REV32.8.1 HEX to avoid file corruption from webpage text conversion.
- Select the local HEX and verify the target
Refresh the local list and let the tool match the ESC name. Start flashing only after manually confirming the hardware target.
- Recheck each ESC and test without propellers
Read the versions and settings of all four ESCs again. Check RPM data, consistent starting, and temperature before a controlled test flight.
FAQ
What effects can the 32.80 bug have?
The video explains that inaccurate RPM readings reduce RPM Filter effectiveness and may increase noise or cause low-throttle twitching. Mechanical and configuration problems still need to be ruled out.
Why not save an individual HEX directly from the GitHub webpage?
The author is concerned that webpage or text conversion could insert unexpected characters, and recommends downloading the complete official ZIP and extracting the firmware files unchanged.
Why flash the ESCs one at a time?
The batch-flashing list in the video did not show 32.81, so the author used the local HEX procedure for individual ESCs and checked each target separately.
Should I still flash 32.81 today?
Do not decide solely from a 2021 video. Check current guidance from the hardware manufacturer and BLHeli tools, including known issues, and prefer a currently supported version suitable for the target.
Why must the propellers be removed before flashing?
Connecting, reading, and testing ESCs can drive the motors. Removing the propellers is a basic requirement to prevent injury from an unexpected start.
Full timeline transcript
Transcripts are arranged according to video time, making it easy to quickly locate the explanation content. Transcript language: Simplified Chinese.
Hello everyone, I am Corin. Last week I posted about a bug introduced in BLHeli 32.8 that greatly reduces RPM Filter effectiveness because the RPM information is read inaccurately. Some people asked how to update to 32.81, so I am recording one demonstration for everyone. If you do not know how yet, you can watch this; I hope it helps. First, we go to the official BLHeli 32.8 GitHub repository.
Be sure to download the latest BLHeliSuite32 configurator. I tried older versions and they did not work; you need the latest one. For example, I am using Windows, so I download the Windows version. The version numbers here are a little confusing: this says 32.809, but it is actually the latest. Once downloaded, extract it somewhere, then open the folder and—
—open the BLHeliSuite32 configurator’s Windows UI. Now we follow the usual procedure for flashing ESC firmware: connect the aircraft, connect battery power, establish the connection, and read the ESCs. I have already flashed mine, so it now shows 32.81. Yours may show 32.8, and this area will not show Betaflight.
How do we flash it? Last time I flashed them individually. Let us first check whether the batch-flashing option has it. The batch list does not have the required version, so we need to flash them one at a time. How? Go here and click Flash. After clicking, let us see what we can select. It is missing here too. What can we do? Select Ignore here, then—
—go back to the repository for the HEX file. The transcript calls this location “REV4.” There is a new folder here, REV32.8.1. You can open it and download a file individually, but I do not recommend that. Converting it through a text file may insert strange characters and make the firmware—
—corrupt. The best method is to download the entire repository here: click Code, then Download ZIP. Once downloaded, extract the HEX file. Extract the HEX referred to here as “32.8e.” Simply take it out of the archive. Put it in the HEX-file folder so it will be easier to find later. Copy it from the ZIP into that folder.
After copying it, return to the configurator, refresh, and select Ignore again. It opens the firmware we just copied. Go into that folder. It has already used your ESC name to match the corresponding firmware by default. Select that file—
—then choose Yes, and flashing begins. I have already flashed it, so I will not do it again. That is how to flash this 32.81 firmware. I hope it helps. Please like, save, and share the video. I am QuadRank; see you next time.
