Navigating BIOS blindly with keyboard

Question

Background: I have a Dell T5810 with BIOS A34. It works fine with UEFI. However, I have recently enabled Secure Boot. This turns out to disable my graphics card (an Asus GeForce GTX 1050 Ti), presumably because its firmware isn't compatible with Secure Boot. Since the workstation doesn't have built-in graphics, I now have no display. The system does boot; I can still access its Linux install remotely, but the main display remains blank at all times, even while booting. It leaves me in a catch 22 that I can't just disable Secure Boot again, because I can't see the BIOS menu anymore! Others have run into this issue before. My options to disable Secure Boot without a display seem to be: Reset the BIOS NVRAM on the motherboard -- doesn't work for me (with the battery technique). Temporarily install a different graphics card -- unfortunately, I don't have one readily available... Based on online videos of people navigating the BIOS, I have now tried to disable Secure Boot blindly, with the keyboard: Repeatedly tap F2 (to get into the BIOS, around the time NumLock lights up) 8 x ArrowDown (to get to the 'Secure Boot' entry, would be 9 x on a laptop with an additional 'Battery' entry) Enter (to expand the entry) 1 x ArrownDown (to get to the 'Secure Boot Enable' entry) Enter (to enter the Secure Boot panel?) Enter (to select 'Disable'?) Enter (to confirm 'Yes' in the popup) Esc (to exit the BIOS) Enter (to confirm 'Yes' in the popup and save the changes) This sequence and many variations with SpaceBar and Tab don't seem to work. Esc mostly reboots right away, suggesting I haven't changed any settings. After a couple of days, I'm running out of ideas. Can someone with a functional display provide a working key sequence to disable Secure Boot? Thanks!

DELL-Cares · Answer

We tried reaching you on a private message asking for the Service Tag number to ascertain the warranty but did not receive a response. Please feel free to reply to the private message whenever you are available.

Eric0110 · Answer

More options to disable Secure Boot that seemed promising but didn't work:

Access Linux remotely and use the Dell Command Configure tool to change the BIOS settings -- the tool allows to change any setting, but not Secure Boot.
Access Linux remotely and update the firmware of the graphics card -- however, when booting in secure mode, Linux doesn't allow updating the firmware.

That's all pretty ironical. Security first!

What eventually did work for me:

First temporarily: change a setting on my HP monitor: "DisplayPort version" from 1.4 to 1.2. I then got a display at boot time again, so I could enter the BIOS and disable Secure Boot. In general, using a different monitor or a different monitor connection may help.
Then permanently: apply the Nvidia Graphics Firmware Update for DisplayPort 1.3 and 1.4 Displays. In general, updating to the latest firmware may help.

Eric0110 · Answer

For the sake of completeness, I'll document my findings for navigating the BIOS with the keyboard. I couldn't test it blindly anymore, but it may help others.

The relevant parts of the BIOS menu look as follows:

General (folded open initially)
- System Information
- Battery Information (only on laptops)
- Boot Sequence
- Advanced Boot Options
- UEFI Boot Path Security (only in recent BIOS verisons)
- Date/Time
System Configuration
Video
Security
Secure Boot (not folded open initially)
- Secure Boot Enable
- Expert Key Management
.....

You can disable Secure Boot with the keyboard with the following key sequence:

Boot up the computer
When the NumLock LED lights up, press F2 (to get into the BIOS)
ArrowLeft (to close the "General" entry)
4 x ArrowDown (to get to the "Secure Boot" entry)
ArrowRight (to expand the entry)
ArrownDown (to get to the "Secure Boot Enable" entry)
Tab (to enter the Secure Boot panel)
Enter (to select the "Disabled" radio button)
Enter (to confirm "Yes" in the popup)
Esc (to exit the BIOS)
Enter (to confirm "Yes" in the popup and save the changes)

You probably need to enable legacy boot ROMs as well:

Boot up the computer
When the NumLock LED lights up, press F2 (to get into the BIOS)
3 x ArrowDown (to get to the "Advanced Boot Options" entry)
Tab (to enter the Advanced Boot Options panel)
Enter (to toggle the checkbox "Enable Legacy Boot ROMs")
Esc (to exit the BIOS)
Enter (to confirm "Yes" in the popup and save the changes)

If nothing else works, you could try loading the default BIOS settings:

Boot up the computer
When the NumLock LED lights up, press F2 (to get into the BIOS)
F9 or Alt-F (to load the default settings)
Esc (to exit the BIOS)
Enter (to confirm "Yes" in the popup and save the changes)

In my experience:

If Esc reboots the computer without waiting for confirmation, you haven't made any changes in the BIOS settings.
Pressing Esc in a confirmation dialog doesn't do anything.
If Esc (possibly with Enter) doesn't reboot the computer, you may not be in the BIOS. This may be helpful to check if all blind attempts fail.

Precision Fixed Workstations

Navigating BIOS blindly with keyboard

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