Recently a few customers had troubles installing RHEL6 or RHEL5 on the HP Proliant Servers DL380 Gen9 or DL360 Gen9
These machines come with UEFI boot mode enabled by default. RHEL/AMD installation from our kickstart will not start in UEFI mode.
The solution is to switch the boot option permanently to Legacy BIOS mode.
Here is a short how-to:
During machine boot press F9 to enter System Utilities -> System Configuration -> BIOS/Platform Configuration (RBSU) -> Boot Mode -> Legacy BIOS Mode
And now the same with a few screen shots: