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  1. #1

    [SOLVED] command-line BIOS boot order change?


    I'm trying to automate OS installation. I've setup PXE and able to do network installation. For installation, I'm changing the BIOS boot order to boot from network.
    Once the OS installation is over, I need to manually change the BIOS boot order to boot from hard-disk.

    Can BIOS boot order be changed using programs/command-line so that i can eliminate human intervention in the installation process by changing back to the original boot order by program/commands?


  2. #2
    I've done some more research on this.
    It seems we can change the BIOS options using BIOS run-time services.
    These BIOS run-time services needs to be invoked in real mode or 16:16 protected mode.

    It seems we can take the machine to protected mode using some assembly code.
    Filling GDT, IDT tables, setting PE bit in CR0 etc...

    Still need to figure out
    1. if it can be taken to "16:16" protected mode
    2. Can these routines be invoked immediately after installing the OS. We need to reboot the machine after installing the OS. So Is it possible to invoke these routines (i.e. entering protected mode, changing the BIOS boot order) before this reboot? I need it to do before reboot because if it reboots without changing the BIOS boot order, it will again install the OS from network.

    Any ideas/pointers are highly appreciated.


  3. #3
    It seems it is not possible to enter 16:16 protected mode.
    I've solved this problem in different manner.
    I've selected to boot always from Network card in BIOS.
    Using PXE, I'm controlling whether to give a new OS image [or] to re-direct to local hard-disk. So in this case no need to change the BIOS boot order dynamically.


  4. $spacer_open

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