A206 carrier board with TX2 NX - no 3v3, no USB, flaky HDMI

TL;dr: The Seed Studios A206 carrier board requires a modification to reliably run TX2 NX modules. See linked post below for the mod.

I recently picked up a Seeed Studios A206 carrier board and a TX2 NX module. I ran into frustrating issues with flashing and booting:

  • Board appeared dead when power applied - no power LED
  • Despite no LED, module did appear in lsusb output and was detected by sdkmanager
  • sdkmanager GUI failed to flash with an error similar
    INFO: Flash Jetson TX2 - flash: UnicodeDecodeError: ‘utf-8’ codec can’t decode byte 0xa4 in position 16: invalid start byte
  • I was able to flash using the flash.sh script
  • While flashing, the A206 power LED came on
  • After flashing, the TX2 NX module did appear to boot, but HDMI didn’t appear
  • After some time a USB-serial interface appeared on the host machine from the micro-USB port
  • On 40-pin header, 5v was present but 3v3 was dead
  • VUSB was not present on any of the USB-A ports
  • Switching to a different monitor, I found the HDMI port was active with the setup screen, but I could not use USB keyboard

While desperately trying to find a schematic for the A206 board (which I would still love to find), I stumbled across this thread.

I was skeptical, but I had no other leads. I gave a half-hearted effort at removing the resistor with a soldering iron I decided to go for broke and snip the resistor. If it is in fact just a pull-down resistor and if I need to replace it, the exact value is not critical so I don’t need to recover the component to reuse or at least measure.

RESULT: PASS

Removing the resistor mentioned in the linked post fixed all of my problems. The board now flashes fine with sdkmanager, the HDMI and USB ports work, the 3.3v rail is alive, and the power LED comes on even if the board is in recovery mode.

This appears to be a mandatory modification to reliably run a TX2 NX module with the A206 carrier board. I’m not sure how it affects other modules.