Flashing Bluejay with esc-configurator — a step-by-step guide
The whole flashing process takes about five minutes once you've done it once. Here's the complete walkthrough, including the gotchas nobody warns you about.
If you want motor music, the first thing you need is firmware that can actually play it well. For SiLabs-based ESCs — which is to say almost every 5-inch quad built in the last five years — that means Bluejay. Here's how to flash it from scratch, written for someone who's never done it.
It really does take about five minutes once you're set up. The first time is slower because of the inevitable "wait, which driver?" detour. Let's get that out of the way.
What you need
- A quad with BLHeli_S-compatible ESCs (check your ESC product page — if it says "BLHeli_S" you're fine).
- A USB cable to connect your flight controller to your computer.
- A charged flight battery. This is the one everybody forgets — keep reading.
- Google Chrome or Microsoft Edge. The web flasher uses WebSerial, which Firefox and Safari don't support yet.
Step 1: plug in the battery first
This is the gotcha. The ESCs are powered by the flight battery, not by USB. If you connect only the USB cable, the flight controller lights up and the configurator connects fine — but the ESCs are dead, and the flasher will fail to detect them with a confusing "no ESC found" error.
So: connect the flight battery to your quad before you plug in USB. Every time. If you ever get "no ESC detected", 90% of the time it's because the battery isn't connected.
(Props off, obviously. You're about to spin motors during detection.)
Step 2: open the configurator
Go to esc-configurator.com in Chrome or Edge. Click Connect, pick your flight controller's serial port from the browser dialog, and the configurator links up.
If no port appears, you're missing the USB driver. Most FCs use a CP210x or CH340 chip — install the matching driver from SiLabs or WCH, replug, and the port shows up.
Step 3: read the ESCs
Click Read Setup. The configurator talks to each ESC through the flight controller and reports back what firmware is on them. A fresh quad usually shows stock BLHeli_S.
You'll see four ESC cards (one per motor). If you only see two or three, one ESC isn't responding — usually a bad solder joint or a motor wire that came loose. Worth fixing before you continue.
Step 4: select Bluejay
In the firmware dropdown for the ESCs, choose Bluejay and the latest stable version. Pick the right variant for your ESC's MCU and PWM frequency — the configurator usually pre-selects the correct one based on what it read, so unless you have a reason to change it, leave it.
Click Flash All. Each ESC gets written in turn. Don't unplug anything while this runs. It takes 20–40 seconds for all four.
Step 5: set your melody
Once Bluejay is on, open the Melody Editor. This is where your song goes. Each ESC gets its own RTTTL string — paste one per motor. Generate them with the converter (it splits a MIDI into one melody per motor automatically) or grab a ready-made set from the song library.
Paste each motor's string into the matching slot, click Accept to validate, then Write Melodies. Bluejay stores the melody in a separate flash region from the firmware, so you can change the song any time without re-flashing the firmware itself.
Step 6: reboot and listen
Unplug the battery, plug it back in. On power-up the ESCs play their startup beeps — and now those beeps are your song. Arm the quad (props still off!) and you'll hear it again.
Common problems
- "No ESC detected". Battery not connected. See step 1.
- Only some motors play. One ESC didn't take the melody — re-write melodies, or that ESC has a hardware fault.
- The song plays but sounds wrong / out of tune. Probably an octave-range issue. See our post on fitting songs into the byte budget.
- Browser won't connect. You're not on Chrome/Edge, or you're missing the USB driver.
A word on safety
Flashing firmware to your ESCs is generally safe and reversible — you can always flash back to stock BLHeli_S. But you are spinning motors during detection, so props stay off until you're completely done. And don't flash on a battery that's about to die mid-write; a half-finished flash can leave an ESC in a weird state (recoverable, but annoying).
That's the whole process. Once you've done it once, the next quad takes five minutes flat.