Ferret

Turns on the hidden dev menu in your OP-XY's te-boot - in your browser.

No firmware is read or written, no keys are involved, and nothing is sent to a server. The page talks to the unit's own USB MIDI interface and flips a service flag the firmware already has.

Dev mode enables options that could be dangerous, don't enable it unless you know what you're doing.

How this works

te-boot (the OP-XY's bootloader) has a hidden dev mode. When it is on, the main menu gains an entry 3. dev menu.

  1. The flag. te-boot turns dev mode on when the file bootloader.dev exists - or at runtime through a console command, 0xAC. This page uses the command, so nothing is flashed.
  2. The challenge. Before acting, 0xAC checks a 16-byte response derived from a value the unit itself reports: command 0x1F returns OTP field 0x13, and the response is that field XOR 99 4A F3 ED. The page reads the field live from your unit and computes the response - no secret is stored on this site.
  3. The transport. While the te-boot menu is on screen, the unit offers a USB MIDI interface. The console commands travel inside TE SysEx messages (F0 00 20 76 21 66 … F7) carrying the same te-serial frames te-boot's internal console uses. The page probes the ports and finds the unit itself.
  4. No readback. te-boot has no command that reports dev mode (the flag is only used to render the menu), and 0xAC deliberately sends no reply - so the menu on the unit's screen is the one and only confirmation. The page asks you to read it.
  5. Reversible. Plan B below can remove the marker again (te-boot deletes bootloader.dev and clears the flag). This page never touches firmware, SPI or the OS partitions.
  6. Local only. There is no server: the page only sends MIDI messages to your unit over USB.
  1. 1ok

    Browser check

    Checking browser support...

  2. 2ok

    Put the OP-XY into te-boot

    1. Power the OP-XY off.
    2. Hold the COM key while switching it on. The screen shows the te-boot menu.
    3. Connect it to this computer with a USB cable and stay on that menu - the unit's MIDI interface comes up with it.

    Then press the button: Chrome will ask for MIDI (SysEx) access - click Allow.

  3. 3ok

    Connected unit

    This is what answered the te-boot probe over MIDI.

  4. 4ok

    Enable or disable dev mode

    Check the OP-XY screen first: if the menu already shows 3. dev menu, dev mode is on - nothing to enable.

    Both buttons read OTP field 0x13 from your unit (command 0x1F), derive the 0xAC response from it, and send the command: Enable writes te-boot's bootloader.dev marker, Disable deletes it.

    Seeing the result: te-boot only redraws its menu when you navigate - after either button, go to another menu and back: press 8 (system menu), then 8 (back). The 3. dev menu entry then appears or disappears.

Plan B - manual controls

Every wizard step as an individual button.

MIDI

te-boot

Dev mode

Reference - exact bytes, no device needed

Live log