Kontron AM4020 uEFI BIOS - Manual (Page 65)

AM4020 uEFI BIOS Updating the uEFI BIOS
ID 1036-5670, Rev. 3.0 Page 59
P R E L I M I N A R Y
7. Updating the uEFI BIOS
BIOS updates are typically delivered as an update CD ISO image. This ISO image needs just
to be burned to a CD and booted. Follow the menu for updating the uEFI BIOS. For further in-
formation refer to the update CD documentation.
7.1 BIOS Redundancy Strategy
The AM4020 has two sets of uEFI flash banks to form a redundancy strategy. The basic idea
behind that is to always have at least one working uEFI Flash bank available regardless if there
have been any flashing errors or not.
7.2 Updating Strategy
To always maintain at least one uEFI flash correct, the update CD uses the following update
procedure:
1. Switch to the second flash bank.
Since the update CD always changes the flash bank prior to doing any updates, the uEFI
BIOS that was used to actually boot the board and is therefore known to be good is pre-
served for backup.
2. Update the second flash bank.
This flash is now selected as active boot flash.
The update CD will not allow to flash both banks at a time. Flashing both banks would destroy
the backup version and therefore break the redundancy.
If you want to have the same BIOS version on both flash banks, then simply run the update CD
twice.
7.3 uEFI BIOS Recovery
In case the uEFI BIOS update has failed due to power loss, the MMC firmware will automati-
cally fall back to a redundant uEFI BIOS flash bank. A new attempt to perform the uEFI BIOS
update can be started once the power is back on.
If the updated uEFI BIOS is not suitable for the system, the selection of the redundant flash
bank must be done manually. An example of a reason for unsuitability is the use of an older
uEFI BIOS version with missing features.
7.4 Determining the Active Flash
Sometimes it may be necessary to check which flash is active. In addition to the Get Control
State
IPMI OEM command, the kboardinfo uEFI Shell command can also be used to deter-
mine the currently selected flash bank. For further information, refer to Chapter 6.2.2, kboard-
info uEFI Shell Command.