Specifying boot devices in BIOS mode […]
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Specifying boot devices in BIOS mode
In the BIOS mode the boot devices are organized by type of devices (Hard Drives, CD/DVD, and Network). For each type it is possible to define a boot order. This is done in the Boot Menu of the UEFI setup program by clicking on the corresponding BBS (BIOS Boot Specification) priorities entry located at the bottom of the Boot Menu page (you may have to scroll down to find them).
For example if you click on the Hard Drive BBS Priorities you will enter a submenu that presents all the drives connected to the system. Here you can define the boot order for the Hard disks. For example you can specify an SDD as the first priority (Boot Option #1) and a HDD as the second priority (Boot Option #2). This implies that the system will first try to boot from the SSD and if this fail it will try to boot from the HDD.
The same prioritization procedure can be used for the CD/DVD as well as for the Network devices.
Note that the Network Devices BBS Priorities entry only shows up if you have enabled the LAN (Intel / Realtek) Oprom options.
Once you have defined the ordering for each type of devices you need to specify the overall priority. This is done in the Boot Option Priorities section of the Boot Menu. For example you can define to use the CD/DVDs first (Boot Option #1) and then to use the HDs after (Boot Option #2). Note that in the menu displayed you will only see the device with the highest priority for a specific type. For example if you have several HDs you will only see the highest priority one (the SDD in our previous example).
Using the above examples the boot manager would first try to boot from the CD/DVD. If this fails it would try to boot from the SDD and if this fails it would try to boot from the HDD.
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... Of course in UEFI mode the BBS specifications are totally ignored as the order of the boot sequence is now defined by the EFI boot manager.
