Supermicro X12 Secure Boot Configuration Instructions page 9

Step 2. For the changes to take effect, press <F4> to save the settings and exit the BIOS
Setup utility.
Step 3. Press <Del> during system boot to enter the BIOS Setup utility. Navigate to the
Security tab to enter the Secure Boot menu. Set CSM Support to Disabled as mentioned in
Section 1.
For the changes to take effect, press <F4> to save the settings and exit the BIOS Setup utility.
9
Secure Boot Settings