So you’re going to upgrade your HP ProLiant Gen 8 or HP ProLiant Gen 9 BIOS. HP is offering SP99341 and SP99406 for that, respectively. They allow you to create a bootable USB drive from which you can upgrade the server’s BIOS.
Except that it doesn’t work. You may get an error message stating the drive is in use by an other process or maybe it all seems fine but just doesn’t do anything.
The instructions state that you need a formatted USB drive large enough for the BIOS upgrade. The stick shouldn’t be larger than 32GB though. The instructions are wrong. For SP99341 (the Gen 8 version) you need to complete remove all partitions from the drive. For SP99306 (Gen 9) you need an unformatted partition.