Three free web apps support Coral, Firmware Updater, Preset Manager and Waveform. All run in your browser. The Firmware Updater builds and flashes firmware, the Preset Manager builds and manages presets, and the Waveform Generator makes wavetables.
9.1 Firmware Updater
The Firmware Updater does three things. You choose your 10 engines or less. The OXI build server compiles a custom firmware. You flash it to Coral over USB. Use Chrome or Edge, which support WebUSB.
Step 1 · Put Coral in update mode
Hold the BOOT button on the Daisy board inside the module. Connect Coral to the computer by USB. It appears as a DFU device. Power it from USB only, with nothing else connected.
Step 2 · Connect
Click Connect Coral and select the DFU device. The app can read back and show the firmware currently installed.
Step 3 · Build or choose firmware
- Start from a shipped layout in the preset menu, or pick your own 10 engines in the grid. The chosen engines fill the 10 slots in order.
- Watch the Flash and RAM meters. Green means it will build. Some engines are large (FMX7, PIANOZ and STITCHER especially), so a combination of several heavy engines may not fit. The meters tell you before you build.
- Leave WAVPLAYER out of your 10 and Coral drops the sampler from the build. Its memory comes back. That leaves room for heavier engines.
- Your settings are never touched. Flashing changes the firmware only: your options live on the SD card and are read from there on the next boot.
- Click Build firmware. Every build compiles a fresh firmware on the server. You can also save your 10-engine layout as a .json file to reload or share. You can print a one-page cheat sheet for your build.
NOTE Instead of building, you can switch to the Upload .bin tab and flash a .bin you already have.
Step 4 · Flash
Do not unplug the module while it flashes. Click Flash to Coral and wait. Coral restarts on the new firmware when it finishes.
CAUTION Flashing replaces the firmware, not your SD card. Your presets, samples and wavetables stay on the card. If you added an engine that needs files on the card, make sure they are there. PIANOZ needs HOUSEKEYS.PCM and RHODES.PCM in System/. FMX7 needs its DX7 banks (Section 8.1).