I installed BunsenLabs on a roughly 2005 HP computer, but every startup reports that \EFI\debian\ could not be found. It continues to the BunsenLabs boot screen briefly, then shows "couldn't parse dbx signatures: -74" before entering emergency mode. What might be causing this, and how can I get the system to boot normally?
2 Answers
Check whether Secure Boot is enabled in the firmware settings. The dbx message is related to the firmware’s revoked-bootloader database, and it can appear when that database is unreadable or when the bootloader is being checked. If your firmware has a Secure Boot option, try disabling it and then test the installation again.
A computer from around 2005 probably predates UEFI Secure Boot, so the dbx warning may not be the main problem. The missing EFI path could mean the system was installed in UEFI mode while the machine is booting in legacy BIOS mode, or the EFI boot files were not installed correctly. Check the firmware’s boot mode and make sure it matches the installation mode; on an older machine, reinstalling in legacy/BIOS mode may be the appropriate choice.
If the machine was first released around 2006, it is unlikely to support Secure Boot at all, so I would focus on the BIOS-versus-UEFI installation mode and whether the bootloader was written to the correct disk.

I’m having trouble finding that option. Could it be unavailable because this computer is quite old?