Software Tuning, Performance Optimization & Platform Monitoring
Discussion regarding monitoring and software tuning methodologies, Performance Monitoring Unit (PMU) of Intel microprocessors, and platform updating.

Overwrite Locked Bits in a Memory Controller


Hi Everyone,

     I am in dire need of overwriting a locked register named DIMM Memory Technology register (link ).

     My objective is to disable a rank selectively.

       Page No 427.

       The field positions are marked as RW-LB. Indicating that one can bypass them provided lock bypass

       bits are enabled. I am very sure that the BIOS does write to those fields because I can observe the

       values being changed each time I change my memory configuration by a difeerent DIMM layout.

       My problem is that nowehere  have I found a way to do so. Even the manual just mentions it but

       does not describe it.

       One post having the same question has been unanswered for a long time. If its confidential,

        I would welcome if any one would let me know that or otherwise any help will be deeply appreciated







0 Kudos
2 Replies
Black Belt

Such a information could be classified under NDA and provided only for kernel/BIOS developers.

0 Kudos

Hello Saptarshi,

I don't know of any way to override the bits if they are locked. Usually if someone needs to do this sort of thing, they have to get BIOS folks to create a special BIOS that doesn't lock the bits or maybe they add a BIOS boot setup screen which allows you to change the settings at boot time.

Getting a special bios is a very difficult thing to do and requires a lot of justification.

0 Kudos