Z240 Tower: Secure Boot Configuration factory default changed in latest motherboard BIOS

[MRFSYS]

the factory default for "Secure Boot Configuration" changed in latest motherboard BIOS version:

On our HP Z240 tower workstation,

prior BIOS versions had 2 choices:

 "legacy support disabled" "secure boot enabled"

 "legacy support enabled" "secure boot disabled"

now there are 3 choices:

 "legacy support disabled" "secure boot disabled"   <---  latest FACTORY DEFAULT

 "legacy support disabled" "secure boot enabled"

 "legacy support enabled" "secure boot disabled"

Outdated Maintenance and Service Guide said this:

[MRFSYS]

Allow me to elaborate a bit here:

We moved a 6-port Icy Dock cage to our Z240 Tower workstation, BUT

the Highpoint controller started acting strangely:

during POST, some of the SSDs wired to that controller

started showing 100% utilization.

We updated that controller with the latest AIC BIOS and latest driver,

but the problems persisted e.g. Windows 10 x64 also began to lock-up.

We also tried updating the motherboard BIOS, using HP Support Assistant.

The latest motherboard BIOS appeared to install AOK,

but the SSD problems continued to persist.

So, it was time for more trials-and-errors (mostly errors).

After all those errors, on a lark I started browsing the menus

in the latest motherboard BIOS, and that search helped to isolate

the factory default had changed in Secure Boot Configuration.

THE FIX:  changing Secure Boot Configuration to

"legacy support enabled" / "secure boot disabled"

Now the AIC option ROMs are appearing normally during POST

(Highpoint RocketRAID 2720SGL and a 2.5GbE PCIe x1 AIC).

Hope this helps.

p.s.  I believe this problem should be escalated to HP's motherboard BIOS specialists,

because factory defaults may have changed in the BIOS for other HP PCs, not merely the Z240.

[MRFSYS]

I should add that I also made sure that each PCIe expansion slot was set to the correct "Gen" in the BIOS menu

e.g. Highpoint RocketRAID 2720SGL and our 2.5GbE x1 AIC are both "Gen2";

an x4 M.2 NVMe adapter is set to "Gen3".  The x16 PCIe expansion slot is empty (for now),

because that PC is using integrated graphics.