D100H Firmware Update Pops Up and Stalls at 0%

wg990416

Title: D100H — Unexpected firmware update window, stuck at 0%, and repeated upgrade errors
Hello Ulanzi Support,
I would like to report a recurring firmware update issue with my D100H.
Environment

• Device: Ulanzi D100H
• Device firmware reported in logs: 1.3.8.1
• Ulanzi Studio: 3.4.8
• OS: Windows
• Connection: Bluetooth via a USB Bluetooth adapter
  

Symptoms
While Ulanzi Studio is running in the background with its main window closed, a firmware update window unexpectedly appears without me manually starting an update.
The update window remains at 0% for more than 10 minutes. However, the D100H continues to respond normally during this time. Closing and restarting Ulanzi Studio appears to restore normal operation temporarily.

Log findings
A review of the available SDK logs found repeated startDeviceUpgrade requests and deviceUpgradeError messages with errorCode: 6.
Some attempts include progress updates before failing, so the issue may involve actual upgrade attempts rather than only an incorrectly displayed window.

For example, on November 12, 2026, the logs show the following sequence. All timestamps below are reproduced as recorded in the local logs:
18:38:50.773  deviceVersion: 1.3.8.118:38:52.001  startDeviceUpgrade18:39:00.985  deviceUpgradeError: errorCode 618:39:00.985  timeout, removeCurrentMessage...18:40:13      deviceKeyEvent messages continued to arrive
Battery status messages also continued after the upgrade error.
Another recurring pattern is an upgrade request with an empty device ID immediately after a device disconnection:

November 13, 202619:01:11.286  DeviceUnlink19:01:11.306  [empty device ID]: startDeviceUpgrade19:01:11.306  findDevice failed: [empty device ID]
A similar sequence appears on November 16:
00:41:53.653  DeviceUnlink00:41:53.671  [empty device ID]: startDeviceUpgrade00:41:53.671  findDevice failed: [empty device ID]
Windows also recorded an application hang for UlanziDeck.exe, version 3.4.8.0, on November 12 at 21:20:47, with an AppHangB1 report.
These logs suggest a possible issue with upgrade triggering or upgrade state handling after an error or disconnection. However, the underlying cause has not been confirmed.

Questions

• Is this a known issue with Ulanzi Studio 3.4.8 or D100H firmware 1.3.8.1?
• What does deviceUpgradeError code 6 mean?
• Why would startDeviceUpgrade be called with an empty device ID after disconnection?
• Is there a supported way to prevent unexpected upgrade attempts?
• Is a fixed version or recommended workaround available?
  

I can provide the original SDK logs and Ulanzi Studio .xlog files privately if needed.
Thank you for your help.