From impulse purchase to pocket studio: The M-Vave FM-1 - Ars Technica

The M-Vave FM-1 is exactly the kind of device I have a weakness for. I may not have an intended use for the frequency-modulation synthesizer, but when a low price meets a high coolness factor, I’m powerless to keep it out of my cart.

Initially billed as a pocket cousin of the famous Yamaha DX7 synthesizer, the FM-1 is a bargain at only $59.72 after fees. At release, it was a cool device that did what it said on the box, but not much else.

But in July, some intrepid tinkerers on Reddit’s r/synthdiy board began reverse-engineering the FM-1’s stock firmware to expand the device’s abilities. By September, custom firmware began appearing. We’re not even through October, and there are already more community firmware projects available to install on the FM-1 than I could ever hope to cover.

I decided to check a few of them out. And just in case you were wondering: Yes, it plays Doom.

Stock firmware and FM1 Open

On October 17, M-Vave announced FM 1 Open, a software package that encourages FM-1 owners to develop custom firmware for the synth-turned-whatever-else-you-can-imagine. Alongside the FM1 Open package came an SDK, a browser-based workbench, and version 15 of the stock firmware, now an open platform you can flash and build on. The unit’s 27 physical piano keys and modest 1.54-inch TFT display lend themselves well to a host of projects, musical or otherwise.

Normally, when an enthusiast community reverse-engineers a closed device, an official patch quickly follows. M-Vave has taken the opposite approach, though. The application source is published under GPLv3, and the company even includes an in-browser emulator to test custom firmware prior to flashing actual hardware. There’s a caveat, however: The underlying synth engine that powers the stock FM-1 package is still distributed as a closed binary, so it’s the application layer of the stack that’s actually open. I don’t think that diminishes M-Vave’s gesture toward the community, but it’s worth noting.

Proceed at your own risk

Before you rush to AliExpress, be aware that flashing custom firmware comes with risks. The JieLi chip powering the FM-1 keeps firmware in a single flash bank, so an interrupted update can leave the device in a difficult-to-recover state. As long as the flashing process completes without interruption, you should be fine. But nothing is foolproof, and there’s always a risk of bricking a device if something goes wrong.

Flashing will also wipe all information on the device. Before you try to load a new firmware package on the synth, back up your saved projects and settings because they will disappear. I was starting from a blank stock canvas, so there was no real risk.

The unit I received was running stock v14 firmware, and community guides repeatedly warn users to update to the stock v15 firmware before attempting to install custom firmware. Guess who didn’t listen? I blindly assumed that since I’d just received my FM-1, it would be running the latest firmware package (v16 now). I was wrong.

Caught in the excitement, I tried to flash Doom directly onto the v14 firmware package, and the installation failed about 80 percent through. Still, it wrote something. The synth worked, but the device stopped speaking the same language as the installers. Thankfully, M-Vave anticipated careless users like me and thoughtfully included a “force-flash” tool in the FM1 Workbench. It restored my unit to stock v15 in about 10 seconds, saving me a huge headache.

The lesson is simple: Always check your current firmware version.

Custom firmware packages

The development scene around the FM-1 is exploding, and new options are appearing all the time. You can browse the listings to see what you might like to try, and a community tip from the fm1-custom-fw GitHub offers some good advice:

While not an absolute hard rule, there is a prominent community recommendation to avoid flashing one custom firmware directly over another. To minimize bricking risks, some users suggest rolling back to the official stock firmware (v15) via M-VAVE’s official updater first, and only then flashing the next custom firmware build. Alternatively, you can use TransitFM1 —a dedicated lightweight bridge firmware by Quixotic7 designed with crash-guarded boot stubs and stock V15 identity emulation to safely transition between custom builds.

Some other tips I picked up along the way from community discussions and my own mistakes:

- Ensure that the FM-1 is fully charged and connected to your PC via USB.