USB-C port (Rear/right corner) suddenly stopped supporting my external monitor

[pawpeter]

Issue Summary

The rear/right corner USB-C port suddenly stopped supporting external displays and appears to provide reduced power compared to the second USB-C port.

The issue appeared after a shutdown/startup cycle on Friday, August 21, 2026.

Timeline

• Thursday night: Laptop remained powered on overnight.
• Friday morning: Rear/corner USB-C port was functioning normally with external monitor(s).
• Friday: Laptop was shut down before leaving home.
• Friday afternoon/evening: After powering the laptop back on, the rear/corner USB-C port no longer functioned correctly for external displays.

USB-C Port Layout

Right side of laptop:

1. Rear corner USB-C port (affected port)
2. USB-C port next to power connector (working port)
3. HP power connector

Symptoms

Rear/Corner USB-C Port (Affected)

Works

• Poly BT700 USB adapter powers on and functions normally.
• Windows detects USB devices connected to this port.
• USB-C hub triggers device detection activity in Windows.

Does Not Work

• Direct USB-C monitor connection.
• External monitor connected through USB-C hub.
• Portable USB-C monitor that normally receives power and video over USB-C.

Additional Observation

• Portable USB-C monitor does not receive sufficient power from this port to operate normally.
• Same monitor operates normally from the other USB-C port.

USB-C Port Next to Power Connector (Working)

Works normally with:

• Lemorele Aluminum USB-C 11-in-1 Hub
• External monitors
• Portable USB-C monitor
• USB devices

No issues observed.

Troubleshooting Performed

Monitor and Cable Validation

Tested:

• Original monitor and cable
• Second identical monitor and cable

Results:

• Neither monitor works from the rear/corner USB-C port.
• Both monitors work correctly from the USB-C port next to the power connector.

Conclusion: Monitor and cable failure ruled out.

USB-C Hub Validation

Device tested:

• Lemorele Aluminum USB-C 11-in-1 Hub (dual HDMI outputs)

Results:

• Functions normally when connected to the USB-C port next to the power connector.
• External monitors operate correctly through the hub.
• Hub is detected by Windows when connected to the rear/corner USB-C port.
• External monitors do not function when the hub is connected to the rear/corner USB-C port.

Conclusion: Issue follows the rear/corner USB-C port and does not follow the USB-C hub.

USB Device Validation

Device tested:

• Poly BT700 USB adapter

Results:

• Powers on normally (blue LED).
• Functions correctly when connected to the rear/corner USB-C port.

Conclusion: Rear/corner USB-C port is not completely dead and still supports basic USB functionality.

Display Detection Validation

Results:

• External monitor is not detected when connected to the rear/corner USB-C port.
• No additional display appears in Windows Display Settings.

Power Reset Tests

Performed:

• Shift + Shut Down (full shutdown)
• Full power drain:
  • Shutdown
  • Disconnect power
  • Disconnect peripherals
  • Hold power button for 30 seconds
  • Restart

Results:

• No change.

CMOS / BIOS Event

During troubleshooting, the system displayed:

CMOS Checksum Invalid CMOS Reset (502)

The system subsequently booted successfully.

Current BIOS status:

• BIOS Version F.20
• Date and time correct
• Hardware recognized normally

Driver and Update Review

Windows Update History

Reviewed Windows Update history.

Findings:

• No updates installed immediately prior to the failure.
• Most recent updates were installed on August 11-12, 2026.
• The affected USB-C port was known to be functioning normally after those updates had already been installed.

USB Driver Review

Reviewed USB-related driver information in HP PC Hardware Diagnostics.

Findings:

• USB4 Host Router
• USB4 Root Router
• USB xHCI Host Controller
• USB Root Hub

all show driver dates of July 21, 2026.

These driver dates predate the failure by approximately one month.

Current Status

Rear/Corner USB-C Port

• Supports basic USB devices.
• Powers and operates Poly BT700 adapter.
• Detects USB-C hub connection.
• Does not provide normal monitor functionality.
• Does not correctly power a portable USB-C monitor.
• Does not drive external displays directly or through the USB-C hub.

USB-C Port Next to Power Connector

• Fully functional.
• Drives external monitors normally.
• Powers portable USB-C monitor normally.
• Functions correctly with USB-C hub.

Request for HP Support

Please investigate:

• Rear/right corner USB-C port functionality.
• USB-C power delivery behavior for that specific port.
• USB4 / Thunderbolt / DisplayPort Alt Mode functionality.
• Possible relationship between the USB-C port failure and the CMOS Reset (502) event.
• Any available firmware, controller, or hardware diagnostics specific to that port.

Key Observation

The affected USB-C port is not completely failed. It still supports low-power USB devices, but no longer provides normal USB-C monitor power and display functionality. The issue is isolated to the rear/right corner USB-C port.

[Hawks_Eye]

Hi @pawpeter 

Welcome to the HP Support Community! We're here to help you get back up and running.

Thank you for providing such a detailed analysis and for already completing extensive troubleshooting. Based on the information shared, you have done an excellent job isolating the issue to the rear/right corner USB-C port.

The key findings are:

• The affected USB-C port still supports standard USB data functionality.
• Windows continues to detect USB devices and USB-C hubs connected to that port.
• DisplayPort Alt Mode functionality appears to be unavailable on that specific port.
• The port also appears unable to provide normal USB-C monitor power delivery.
• The second USB-C port continues to operate normally with the same monitors, cables, hub, and portable display.
• The issue began after a power cycle and was later accompanied by a CMOS Reset (502) event.

Since the standard power reset procedures, monitor validation, hub validation, device validation, and Windows update review have already been completed, I would suggest focusing on the remaining checks below.

1. Load BIOS Defaults

The CMOS Reset (502) event indicates the BIOS settings were reset or reinitialized.

1. Restart the notebook.
2. Tap F10 repeatedly to enter BIOS Setup.
3. Select Restore Defaults or Apply Factory Defaults and Exit.
4. Save changes and restart.
5. Test the affected USB-C port again.

 

2. Verify Thunderbolt / USB4 Configuration in BIOS

Depending on the platform, USB4, Thunderbolt, and DisplayPort Alt Mode functionality may be controlled by BIOS settings.

1. Enter BIOS using F10.
2. Review Advanced or Port Configuration settings.
3. Confirm any USB4, Thunderbolt, External Display, USB-C, or PCIe Tunneling settings are enabled.
4. Save changes and restart.

 

3. Run UEFI Hardware Diagnostics

Although Windows devices appear normal, hardware diagnostics can sometimes identify USB-C controller issues.

1. Power off the system.
2. Tap F2 during startup to launch HP PC Hardware Diagnostics UEFI.
3. Run:
   • System Tests
   • Component Tests
   • Thunderbolt/USB-C tests (if available on your model)
4. Record any failure IDs reported.

 

4. Reinstall USB4 Controller Devices

Since only the display functionality is affected, reinitializing the USB4 controller may help.

1. Open Device Manager.
2. Expand:
   • USB4 Host Router
   • USB4 Root Router
3. Uninstall the USB4 devices.
4. Restart the computer.
5. Allow Windows to reinstall the controllers automatically.
6. Retest the affected port.

 

5. Reflash the Current BIOS Version

A CMOS 502 event followed by loss of one port's DisplayPort functionality could indicate firmware corruption affecting the USB-C controller.

Even if F.20 is already installed:

1. Download the latest BIOS package for your model from HP Support.
2. Run the BIOS update package and allow it to reinstall the same version if offered.
3. Restart and test the port again.

 

6. Test Outside Windows

To determine whether the problem is firmware-level or operating-system-level:

1. Enter BIOS Setup.
2. Connect a USB-C monitor to the affected port.
3. Check whether any display activity occurs before Windows loads.

If the monitor remains inactive even before Windows starts, it would point more toward the USB-C controller, firmware, or hardware path rather than a Windows driver issue.

 

Assessment

Given that:

• Monitor cables have been ruled out.
• Displays have been ruled out.
• The USB-C hub has been ruled out.
• Basic USB functionality remains operational.
• Display and power-delivery capabilities have failed only on one port.
• A CMOS Reset (502) event occurred during the same troubleshooting period.

The remaining possibilities are typically:

• USB4 / Thunderbolt controller configuration corruption.
• BIOS or embedded controller firmware issue.
• DisplayPort Alt Mode failure specific to that port.
• Hardware failure within the USB-C port circuitry responsible for video and higher-power delivery functions.

If the above steps do not restore functionality, the available software and firmware troubleshooting would essentially be exhausted.

In this regards, I would request you to contact HP service center for further assistance.

Click on the link below and fill in the required details to find the closest service center and their availability.

Service Center Locator: Find an HP Service Center

Please call before visiting a service center.

Regards,
Hawks_Eye

[pawpeter]

Thank you HAWKS_EYE!!

I completed the recommended troubleshooting steps for the rear/right USB-C port and am providing the results below. I also attempted to install the BIOS package currently offered by HP, but I cannot confirm that the package was successfully applied.

SYSTEM INFORMATION

• HP Spectre x360 16-f2000
• Product Number: 7H101UA#ABA
• Serial Number: CND3290H9F
• Operating System: Windows 11 25H2 (Build 26200)
• Current BIOS Revision: F.20
• Current BIOS Date: 04/02/2026

COMPLETED TROUBLESHOOTING

1. Load BIOS Defaults

• BIOS defaults were loaded.
• The affected USB-C port was tested afterward.
• The USB-C display issue remained.

1. Verify Thunderbolt / USB4 BIOS Configuration

• BIOS configuration was reviewed.
• No disabled Thunderbolt, USB4, USB-C, external display, or related port settings were identified.
• The issue remained unchanged.

1. Run HP UEFI Hardware Diagnostics

• HP PC Hardware Diagnostics UEFI updated from version 10.8.1.0 to 10.8.7.0.
• Thunderbolt Test: PASSED
• USB Port Test: PASSED
• System Board Test: PASSED
• Diagnostic logs were saved.

1. Reinstall USB4 Controller Devices

• Both USB4 Root Router (1.0) devices were uninstalled.
• Both USB4(TM) Host Router (Microsoft) devices were uninstalled.
• Windows automatically re-enumerated some of the devices.
• The system was restarted.
• After restart, all USB4 Root Router and USB4 Host Router devices returned.
• Rebuilding the USB4 stack did not restore the affected USB-C port.

1. Test Outside Windows

• Testing was performed within HP UEFI Diagnostics.
• A USB-C hub was connected to the affected rear/right USB-C port while entering HP Diagnostics.
• Diagnostics appeared to pause at approximately 80% during loading.
• Once loaded, the interface became extremely slow.
• The touchpad stopped functioning.
• Touchscreen response was also very slow.
• The cooling fan was running.
• After disconnecting the USB-C hub from the affected port:
  • Interface responsiveness immediately returned to normal.
  • The touchpad resumed functioning.
  • Touchscreen responsiveness returned to normal.
• The system subsequently exited Diagnostics and booted into Windows normally.
• This behavior occurred outside Windows while the hub was connected to the affected USB-C port.

1. Functional A/B Validation

• Monitor failure ruled out.
• Monitor cable failure ruled out.
• USB-C hub failure ruled out.
• The same monitor, cable, portable display, and USB-C hub function normally when connected to the other USB-C port.
• The problem remains isolated to the rear/right USB-C port.
• Basic USB functionality remains available on the affected port.
• Display functionality remains unavailable on the affected port.
• Normal USB-C monitor power functionality also appears unavailable on the affected port.

1. BitLocker Verification Prior to BIOS Maintenance

• BitLocker is enabled on the C: drive.
• Drive encryption status is 100%.
• Protection Status: ON
• Encryption Method: XTS-AES 128
• TPM protector present.
• Numerical Password recovery protector present.
• Recovery information confirmed backed up to both Microsoft Account and Microsoft Entra ID.
• Recovery readiness verified prior to BIOS maintenance.

1. BIOS F.20 Rev.A Download and Installation Attempt

HP currently offers the following BIOS package for this system:

• HP Notebook System BIOS Update (Intel Processors)
• Version: F.20 Rev.A
• File Size: 11.7 MB
• Release Date: April 30, 2026

The downloaded installer reported:

• Version: F.20
• SoftPaq: sp172501
• Effective Date: 04/30/2026
• Category: BIOS
• Enhancement: Provides improved security

The following actions were completed:

• Downloaded the BIOS package.
• Launched SoftPaq sp172501.
• Completed extraction.
• Launched HP BIOS Update and Recovery.
• Selected the option to update the BIOS on this device.
• The utility offered to update the BIOS to version F.20.
• Continued through the update workflow and BitLocker validation steps.
• Verified BitLocker protection and recovery availability.

POST-ATTEMPT BIOS VERIFICATION

After the BIOS update attempt, the system still reports:

• BIOS Revision: F.20
• BIOS Date: 04/02/2026

The system does NOT report:

• F.20 Rev.A
• BIOS Date 04/30/2026
• Any visible indication that the F.20 Rev.A package was applied

Because of this, I cannot determine whether the F.20 Rev.A package was successfully installed, whether Rev.A refers only to the SoftPaq package, or whether the installed BIOS was already considered current.

CURRENT SYMPTOMS

• Rear/right USB-C port still does not provide normal display functionality.
• Same monitor, cable, portable display, and hub continue to work through the other USB-C port.
• Basic USB data functionality remains available on the affected port.
• HP diagnostics pass successfully.
• Real-world port-specific functionality remains impaired.
• Connecting a USB-C hub to the affected port caused abnormal behavior within HP UEFI Diagnostics outside Windows.

CLARIFICATION REQUEST

Please clarify the following:

1. Should successful installation of BIOS package F.20 Rev.A cause Windows System Information or HP System Profile to display "F.20 Rev.A"?

2. Should the BIOS date change from 04/02/2026 to 04/30/2026 after successful installation?

3. Is "Rev.A" a revision of the BIOS firmware itself, or only the revision of the SoftPaq installation package?

4. Is April 30, 2026 the BIOS firmware date, or only the package release date?

5. How can I verify whether SoftPaq sp172501 and BIOS F.20 Rev.A were successfully applied?

6. If the update was not applied because the system already reports BIOS F.20, what method should be used to perform the same-version BIOS reflash referenced in the troubleshooting instructions?

7. Is the same-version reflash intended to rewrite existing firmware in response to the earlier CMOS Reset (502) event?

8. Given the abnormal behavior observed within HP UEFI Diagnostics while a hub was connected to the affected USB-C port, do you still recommend another BIOS reflash attempt, or should the system now be evaluated for a USB-C hardware, DisplayPort Alt Mode, power delivery, or system board fault?

Thank you for reviewing these results and clarifying whether the F.20 Rev.A installation was successfully applied.

Regards,

PAWPETER

[Pallipurath]

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