Ok, let me explain a few things...
When you ask for a BIOS update, regardless of the method (F7, iFlash, EBU) that is used, the process is exactly the same: The BIOS image is placed into memory and the system is rebooted. During the subsequent POST, the BIOS sees the image sitting in memory and installs it.
From time to time, after the reboot, the BIOS will struggle in POST for some reason and its recovery from this struggle will result in the BIOS update being forgotten. The most common cause for such a struggle is with memory initialization. It could be that your DIMM(s) are borderline working.
Before doing anything drastic like replacing the DIMM(s), what I suggest that you do is attempt to perform the BIOS upgrade using the Recovery Method. This is documented here: Intel Desktop Boards Recovery BIOS Update Instructions. In this document, "Recovery BIOS" just means the latest available BIOS file. Take the latest available BIO file (i.e. MY0076P.BIO) and place it on a USB 2.0 flash disk that has been freshly formatted using the FAT32 file system. Insert this flash disk into the system. Remove the BIOS Configuration jumper from the board. Power on the system. It should automatically perform the BIOS update. It will tell you when it is done. Power off, restore jumper to pins 1-2 and then power on again. You should be good to go with the new BIOS then.
Hope this does it,