For new boards with AMI BIOS core 8 (4MB)
Discovered by Jack The Newbie:
Of course, the steps are similar to the standard AMI BIOS Recovery Procedure for internal floppy drives (rename corresponding BIOS File to AMIBOOT.ROM, hit CTRL + HOME after starting the system).
What has to be done (tested on P45 Platinum):
1. An optical SATA Drive needs to be connected to one of the Intel ICH10R SATA ports. {After a lot of testing, I found that it does not work with the same optical drive connected to the SATA Ports hosted by the secondary JMicron Controller. Also, using an optical drive on the JMicron IDE/PATA port does not help either.}
2. A proper BIOS File has to be renamed to AMIBOOT.ROM and burned on an empty CD.
3. CMOS-Clear with main A/C power cable removed from PSU has to be performed. {If this step is not done, the system will reboot after pressing CTRL + Home and will not proceed with recovery procedure.}
4. Press CTRL + Home to trigger BIOS Recovery. -> The system should enter BIOS Recovery Routine. {Will basically work with both USB & PS/2 keyboard. However, a PS/2 Keyboard is recommended as the system will respond earlier to PS/2 Keyboard than to USB Devices.}
What should happen now:
1. After pressing CTRL + HOME the LED Status should change to "Intializing Hard Disk Controller" and there should be access to the optical drive connected to the Intel ICH10R SATA ports.
2. It can take up to 30+ seconds until the BIOS File that was renamed to AMIBOOT.ROM is found. {Drive Bay can be opened to try a different CD without turning off or restarting the system.}
3. When the system finds the BIOS File, LED Status will change to "Testing RTC" and there should be a message on the screen indicating that the Flash Recovery Procedure has started.
4. Since the BIOS File is 4MB in size, it will take a while until the BIOS is actually reflashed.
Its also possible that BIOS recovery on boards with AMIBIOS8 can be done using a FAT-formatted USB stick, containing the renamed BIOS file. Be warned, in some circumstances it may take several moments before recovery procedure actually begins. See Bas' reply below for further information.