HDMI Expansion card interferes with bootable USB detection

See also: USB drives not showing up in BIOS or Boot Manager - #16 by Richard_Quinlivan

System specifications

OS (probably irrelevant): Fedora Linux 41 (Workstation Edition)
Laptop: Framework 13, Intel 13th Gen
UEFI version*: 3.05

Steps to replicate:

  1. Prepare a bootable firmware update drive as described in “How do I enter the BIOS on the Framework Laptop?”. I used a generic USB 2.0 Type A flash drive.
  2. Disable secure boot if it is enabled.
  3. Plug in the bootable USB flash drive.
  4. Restart the machine and enter the boot manager with F12.
  5. Observe the boot options available with an HDMI expansion card connected.
  6. Disconnect the HDMI expansion card.
  7. Observe any changes to boot options.

Expected results: Boot menu should be unaffected.
Actual results: Firmware update drive appears on boot menu only after expansion card is disconnected.

*also applies to a previous 2.x version that I failed to write down