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FLY-D5 Bootloader (Katapult) Recovery

For Unbricking Only
  • This page is for when Katapult itself is damaged: double-clicking RST shows no light, usb-katapult_ cannot be found at all, or the mainboard cannot enter flashing mode.
  • Do not use this page for normal Klipper firmware upgrades; please return to Firmware Compilation and Flashing.
  • The Fly-D5 mainboard can only perform Bootloader flashing via the Type-C USB interface; it ships with Katapult by default and generally does not need reflashing.

Prerequisites​

Download the Katapult firmware matching D5:

Windows file extension display

Windows may hide file extensions. After downloading, please confirm the file name is still FLY_D5.bin and is not saved as .txt or another extension.

The firmware is located in the FLY-Firmware/MainBoard/D directory.

Windows requires the installation of STM32CubeProgrammer and the STM32 DFU driver; Linux / FLYOS uses the automatic flashing command below. You will also need a Type-C data cable that supports data transfer.

Entering DFU Flashing Mode​

Button Positions

The left one is the RST button, and the right one is the BOOT button.

Power-Disconnection Operation

When it is necessary to plug or unplug the Type-C data cable, the printer must first be completely turned off and the power supply disconnected. The button operation in Method 2 itself does not require plugging or unplugging the cable.

There are two ways to enter DFU:

  1. With the mainboard completely powered off, press and hold the BOOT button, then connect a Type-C cable that supports data transmission to the mainboard and the host computer.
  2. When the Type-C cable is already connected, press and hold the BOOT button, then press the RST button, and then release RST and BOOT in sequence.
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After entering DFU, the flashing software should be able to recognize the DFU device (0483:df11).

Flashing Katapult Firmware​

Power-off operation

Before connecting or reconnecting the USB cable, completely turn off the printer and disconnect all other power supplies. Do not let the tool board be powered simultaneously through the printer power supply and the USB interface.

USB connection compatibility

The USB interfaces on some computers may cause unstable flashing due to driver or signal compatibility issues. If the connection fails, try using a different USB interface on the computer or use a reliable-quality USB dock; when the error shown below appears, also check the USB connection and driver first.

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  1. Download and install SetupSTM32CubeProgrammer and the STM32 DFU driver from the auxiliary software download page.
  2. Save the firmware downloaded on this page to a location on your computer that is easy to find.
Windows file extension display

Windows may hide file extensions. In File Explorer, check "File name extensions" to confirm that the firmware is still .bin or .hex, and do not change the file extension.

  1. Confirm that the device has entered DFU flashing mode according to the product tutorial, then connect it to the computer using a USB cable that supports data transfer.
  2. Open STM32CubeProgrammer, select USB mode, refresh the device list, and connect.
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  1. If no error pop-up appears, the connection is successful.
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  1. Click the download icon on the left, and check the flashing options as shown in the figure below.
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  1. Click Browse and select the firmware to be flashed.
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  1. When flashing .bin firmware, set Start address to 0x08000000; when using .hex firmware, keep the address included in the file.
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  1. Click Start automatic mode to begin flashing.
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  1. When the success prompt appears, the firmware flashing is complete.
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Verification and Follow-up Steps​

  • After flashing is complete and there are no errors, first turn off the power, then disconnect the Type-C data cable, and then power the mainboard back on.
  • Quickly double-click RST, and the status light starts blinking; running lsusb should show 1d50:6177, indicating Katapult has been recovered.
  • Katapult is only a Bootloader; after recovery, you must continue to flash the Klipper firmware: Firmware Compilation and Flashing.

Common Failure Causes​

SymptomPossible CauseSolution
Flashing software cannot detect the deviceNot in DFU mode, data cable is charge-only, or driver not installedPress BOOT + RST to re-enter; replace the data cable; install the STM32 DFU driver on Windows
0483:df11 not found in the softwareDevice is not in DFU modeHold BOOT first, then power on, or re-enter using Method 2
Flashing succeeds but no light after double-pressing RSTFirmware file mismatch or hardware abnormalityConfirm that the downloaded firmware is the Katapult firmware for D5; if there is still no response, contact after-sales support
Can enter Katapult but Klipper cannot connectOnly the Bootloader has been restored, and the Klipper firmware has not yet been flashedReturn to Firmware Compilation and Flashing to flash Klipper
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