Luckfox Pico Zero cannot enter MaskROM (2207:110c) on some USB ports — error -71, fixed by switching port

• xutengl

  Posts: 6

  Joined: 2025-08-07 14:24

  2026-01-25 17:13

  Problem
  
  On my PC, the Luckfox Pico Zero is consistently detected as the USB device 2207:0019 during normal boot.
  However, when attempting to enter flash mode, the device with ID 2207:110c never appears. In this state, 2207:0019 also does not show up.
  
  After resetting the board, it is once again detected as 2207:0019, and I can access it normally via SSH or Samba.
  
  
  Investigation
  
  I tested different USB cables and operating systems (Windows 11 and Ubuntu 24.04), but the issue persisted.
  When I tried a different USB port, the problem was unexpectedly resolved. This led me to systematically test all USB ports on my PC.
  
  The following USB ports worked correctly in both normal boot and flash mode:
  

  • usb 3-2 (front, USB-A)
  • usb 3-3.1 (back, USB-A)
  • usb 3-3.2 (back, USB-A)
  • usb 3-3.3 (back, USB-A)
  • usb 3-1 (back, USB-A)

  In these cases, dmesg showed:
  

  Code: Select all

  sudo dmesg -w
  ... new high-speed USB device number 78 using xhci_hcd
  ... New USB device found, idVendor=2207, idProduct=110c, bcdDevice= 1.00
  ... New USB device strings: Mfr=0, Product=0, SerialNumber=0
  

  The following USB ports could detect the device during normal boot, but failed to detect it in flash mode:
  

  • usb 3-4 (front, USB-A)
  • usb 3-5 (front, USB-C)

  In these cases, dmesg showed:
  

  Code: Select all

  sudo dmesg -w
  ... Device not responding to setup address.
  ... device not accepting address 77, error -71
  ... unable to enumerate USB device
  

  When the Luckfox Pico Zero was connected to USB 3-5 through an external USB hub, the PC failed to detect the Rockchip USB device in both flash mode and normal boot mode:
  

  Code: Select all

  sudo dmesg -w
  ... Cannot enable. Maybe the USB cable is bad?
  ... attempt power cycle
  ... Cannot enable. Maybe the USB cable is bad?
  ... unable to enumerate USB device
  

  Findings
  
  These results indicate that the issue is USB-port specific, rather than being caused by the Luckfox Pico Zero hardware, USB cables, or flashing procedure.
  
  
  Further Question
  
  Is it possible to mitigate this issue from the Luckfox device side?
  For example:

  • Can the behavior of `2207:110c` be made more similar to `2207:0019`?
  • Is there a way to improve compatibility with a wider range of USB host hardware?

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