Microsoft is working on ways to protect your system at an even lower level than the bootloader. Many modern computers have UEFI protection, which allows for security in the boot process, and prevents untrusted code from running. This is intended to ensure that some other boot process cannot run and then invoke your Windows bootloader.
This doesn't protect from firmware issues, but Microsoft may have a solution. Working with hardware companies (Intel, AMD), they have a System Guard Secure Launch that provides a way to secure your OS. There's a light explanation at Ars Technica of what this means for you. Essentially, this allows the OS to reset the CPU and ensure untrusted firmware code isn't running.
I won't pretend to know how this works in depth, or what additional levels of security this provides, but I do recognize the problem being worked on here. I also think that criminals (and rogue nation state actors) are making deeper and more complex attacks on systems. We know that compromised code can be a major problem for our servers, and we need better mechanisms to ensure we can trust the platform on which we run our database servers
Just recently there was an alert about a backdoor in SQL Server. This was noted as being in SQL Server 2012 and 2014. At first I was surprised this didn't get more play, then I realized this was an issue with the Windows OS being compromised and then a patch installed on the SQL Server service to allow attackers to log into the database server. Disconcerting, but if someone gains control of the Windows OS, I'd expect they can get into SQL Server.
Security is a problem with database servers, and the number and variety of attacks continues to grow. It pays to be diligent, and certainly, use whatever tools are available. Strong passwords, access controls and low privileged accounts, UEFI, SGSL, set up every security feature you can. After all, data is your organization's most important asset.