Apply the GPT + Active workaround to the Dell Precision Tower 5810

[vangyzen]

Summary

The Dell T5810 fails to boot without the active flag in the pmbr.
Suggest the workaround during installation.

[vangyzen]

$ kenv | grep smbios.system
smbios.system.maker="Dell Inc."
smbios.system.product="Precision Tower 5810"

[vangyzen]

Why is "GPT + Active" not the default? Do we know that it's harmful on some systems?

We're seeing an increasing number of systems that need the workaround. Now we've seen it on Dell systems ranging from entry-level laptops to a high-end workstation. This would seem to indicate that Dell is sharing firmware across the product lines, which could mean that every new Dell system will need this workaround from now until Legacy boot is finally dead.

I don't think the installer has access to the date of manufacture. (I'd love to be wrong.) Failing that, we could look at the BIOS release date and suggest the workaround for Dell systems with a BIOS released in 2015 or later. This will have some false positives when installing on an older system with an updated BIOS, but this might be harmless. I have several Dell systems with 2011-2012 BIOS versions running FreeBSD with GPT. I could set the active flag and make sure they still boot.

For reference:

smbios.bios.reldate="09/26/2015"
smbios.bios.vendor="Dell Inc."

[vangyzen]

By the way, I haven't tested this, partly because I don't know how. If you really want me to test it, please let me know how.

[dteske]

LGTM