Disable serial console from userland (linux)

  • Hello,

    I use a APU2 board with coreboot.

    I have only a remote data connection to this device (with Debian 10 Linux).

    Is it possible to disable the serial console in coreboot with nvramtool?

    I need this because an attached serial device sends permanent data to the serial port and this stops booting up after a restart.


    I found an answer to my question. 8o

    You can change the parameters when you use the combination of flashrom and cbfstool.
    cbfstool is located in util directory of coreboot.

    What to do:

    1. read actual BIOS: flashrom -p internal -r coreboot.bin
    2. extract BIOS parameters: cbfstool coreboot.bin extract -n bootorder -f bootorder
    3. change Parameters in file bootorder
    4. make a copy of the original bios: cp coreboot.bin coreboot2.bin
    5. remove old BIOS parameters: cbfstool coreboot2.bin remove -n bootorder
    6. add new BIOS parameters: cbfstool coreboot2.bin add -n bootorder -f bootorder -t raw
    7. flash new BIOS with new parameters: flashrom -p internal -w coreboot2.bin