How-to: Enter DFU mode

CS 737X CDU
CS 737M CDU
CS 747X CDU
CS 777X CDU

  1. Disconnect USB cable from the CDU.
  2. Press and hold the “INIT REF” key and the number “5” key.
  3. Connect USB cable to the CDU.
  4. The backlight flashes, indicating that CDU has successfully entered DFU mode.
  5. Release the “INIT REF” key and the number “5” key.

CS 737X EFIS

  1. Disconnect the USB cable from the EFIS.
  2. Disconnect the daisy chain cable from the EFIS when it is in the home simulator “daisy chain” mode.
  3. Press and hold the “STD” key.
  4. Connect the USB cable to the EFIS.
  5. The backlight flashes, indicating that EFIS has successfully entered DFU mode.
  6. Release the “STD” key.

CS 737X MCP

  1. Disconnect the USB cable from the MCP.
  2. Disconnect the daisy chain cable and DC power cable from the MCP when it is in the home simulator “daisy chain” mode.
  3. Toggle the “A/T ARM” switch to the “ARM” position and hold.
  4. Connect the USB cable to the MCP.
  5. The backlight flashes, indicating that MCP has successfully entered DFU mode.
  6. Release the “A/T ARM” switch.

CS 320N FCU-L/R

  1. Disconnect the USB cable from the FCU-L/R.
  2. Disconnect the daisy chain cable from the FCU-L/R when it is in the home simulator “daisy chain” mode.
  3. Pull and hold the Barometer Reference Selector Knob.
  4. Connect the USB cable to the FCU-L/R.
  5. The backlight flashes, indicating that FCU-L/R has successfully entered DFU mode.
  6. Release the knob.

CS 320N FCU-C

  1. Disconnect the USB cable from the FCU-C.
  2. Disconnect the daisy chain cable and DC power cable from the FCU-C when it is in the home simulator “daisy chain” mode.
  3. Pull and hold the HDG/TRK Selector Knob.
  4. Connect the USB cable to the FCU-C.
  5. The backlight flashes, indicating that FCU-C has successfully entered DFU mode.
  6. Release the knob.

CS 737X CDU (v2)
CS 737M CDU (v2)
CS 747X CDU (v2)
CS 777X CDU (v2)
CS 320A MCDU

Method A – Automatic

  1. Connect the CDU/MCDU to the computer.
  2. Start the CS Bridge software and wait for the CDU/MCDU to be identified.
  3. When the CDU/MCDU appears in the ‘CONNECTED DEVICES’, click on the specified device card.
  4. On the pop-up page, click the ‘REBOOT TO DFU MODE’ button.
  5. Click the ‘Yes’ button.
  6. The backlight will blink and a USB cable image will appear on the screen, indicating that the CDU/MCDU has successfully entered DFU mode.

Method B – Manual

  1. Disconnect the USB cable from the CDU/MCDU.
  2. Press and hold the ‘INIT REF’ key and the number ‘5’ key.
  3. Connect the USB cable to the CDU/MCDU.
  4. The backlight will blink and a USB cable image will appear on the screen, indicating that the CDU/MCDU has successfully entered DFU mode.
  5. Release the ‘INIT REF’ key and the number ‘5’ key.