5 Replies Latest reply on Feb 8, 2018 11:05 AM by Carlos_A

    Flash descriptor and read/write permissions

    pietrushnic Green Belt

      I'm trying to understand flash descriptor and read/write permissions that can be configured using master region. I'm using MinnowBoard Turbot B and trying to change flash descriptor so it will have any effect in my Linux system, but apparently I have problem with that. I read IFD with chipsec. I was able to modify IFD in below way:

       

      + 0x0060 Master Section:

      ========================================================

      + 0x0060 FLMSTR0   : 0xFDFF0000

      + 0x0064 FLMSTR1   : 0xFFFF0000

       

      Master Read/Write Access to Flash Regions

      --------------------------------------------------------

      Region                | CPU   | ME   

      --------------------------------------------------------

      0 Flash Descriptor     | RW    | RW   

      1 BIOS                 | R     | RW   

      2 Intel ME             | RW    | RW   

       

      Despite that I'm still able to use flashrom to write BIOS region. Why it is still possible ? Who enforce this access rights ?

      Description in Bay Trail datasheet IMO is not clear or I miss some fundamental knowledge about IFD.