KL730 EVM USB Detection Issue on Ubuntu 18.04 – Fastboot/DFUT Connection Failure

Dear Team,

We are currently working with the KL730 EVM Board to deploy and test AI models using Kneron PLUS/DFUT. However, our Ubuntu host PC is not detecting the KL730 board through USB, As a result, we are unable to establish USB communication with the board, which is required for firmware updates and AI model deployment.

1. Hardware & Software Setup

• Board: KL730 EVM
• Host OS: Ubuntu 18.04.6 LTS
• SDK: KL730 SDK 2.0.0
• USB: USB 2.0
• UART: /dev/ttyUSB0 (115200 baud) – Working
• Firmware: Leipzig v1.5.3
• Tools: Fastboot, Minicom, Kneron DFUT

2. Issue & Errors

A. USB Fastboot from Ubuntu:

fastboot --page-size 512 boot signed_4k_bl2_dq_swap_0_standard.bin

Output:

< waiting for any device >

B. USB Fastboot from U-Boot (UART):

setenv fastboot_bootcmd 'echo ok';fastboot -l 0xA00000 usb 1

Output:

No USB device found
USB init failed: -19

3. Troubleshooting Performed

We followed the official KL730 Development Environment User Guide and EVM Board User Manual:

• Configured USB 2.0 OTG mode (USBID_SEL1: OPEN, J65: pins 1–2 shorted).
• Configured SW1 for USB 2.0 Fastboot (SEL[5:3] = 000).
• Verified that Fastboot is installed on Ubuntu.
• Successfully booted the board through SPI NAND and accessed U-Boot via UART.
• Confirmed BL2, BL31, U-Boot, and Linux are loading successfully.
• Verified that the required firmware files, including fw_plus_nand_4k.ubifs, are available in SDK 2.0.0.

Despite these checks, USB communication is still not working.

4. Support Required

Could you please help us clarify the following?

1. USB Drivers: Does Ubuntu 18.04 require any additional USB drivers, kernel modules, or udev rules for KL730 detection?
2. USB Error: What causes USB init failed: -19, and how can we resolve it?
3. Firmware: Is Leipzig v1.5.3 compatible with Kneron PLUS/DFUT? Do we need to flash fw_plus_nand_4k.ubifs or update other firmware components?

Kindly provide the recommended step-by-step procedure to resolve USB detection, install any required drivers, and prepare the KL730 EVM for AI model deployment.

Thank you for your support.