USB and Power Reliability

When to Use This

Use this KB if TezSign does not appear over USB, disconnects unexpectedly, fails to boot from host power, or shows USB timeout errors.

Power Checklist

In some cases, powering the TezSign device only through the OTG USB port may not provide consistent power.

Try these options:

  1. Use the dedicated power port on the TezSign device for independent power.
  2. Use a powered USB hub on the OTG USB port.
  3. Check host BIOS settings so the USB port stays powered.

BIOS Settings

Check these settings on the baker host:

  • USB power delivery in Soft Off state (S5): enabled
  • ErP Ready / EuP Ready / ErP Compliance: disabled
  • Deep S4/S5 / Deep Power Saving / Pseudo G3: disabled
  • Resume by USB Device / Power On by USB: enabled

To enter BIOS from Linux:

sudo systemctl reboot --firmware-setup

USB 3.0 Controller Issues

TezSign USB gadget mode may have issues with USB 3.0 (xHCI) controllers.

Symptoms can include:

  • error -110 or error -62 in dmesg
  • Device gets no power or does not boot
  • Device never appears in lsusb
  • Repeated timeout errors

Try these fixes in order:

  1. Use a different short, high-quality data cable. Avoid charge-only cables.
  2. Use a USB 2.0 port if the host has one.
  3. Place a USB 2.0 hub between the host and TezSign device to force USB 2.0 negotiation.
  4. Check BIOS settings for xHCI mode, USB suspend, legacy USB support, and always-on USB power.

Reset the USB Port

If the device stops responding:

tezbake tezsign advanced usb-port-reset
tezbake stop --signer
tezbake start --signer

Then verify status:

tezbake tezsign status
tezbake info --signer

Any questions/comments/concerns? Please contact the Tez Capital team on Discord or Telegram