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    X220 Tablet Owners-A modified BIOS!

    Discussion in 'Lenovo' started by Raidriar, Nov 13, 2012.

  1. Raidriar

    Raidriar ლ(ಠ益ಠლ)

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    This may be useful for any X220 Tablet owners seeking to run Mac OS X Lion/Mountain lion on their hardware. i have patched the BIOS to disable locking of MSR bit 0xE2, which locks the package c state limit. You guys may know this as the necessity to patch appleintelcpupowermanagement.kext, because those registers are typically locked, causing the system to kernel panic. With this bios update (hopefully), you will be able to use native speedstep without patching, since the registers will remain open. This will also grant you package c state control in windows via throttlestop THIS BIOS IS UNTESTED, TRY ARE YOUR OWN RISK. I AM NOT RESPONSIBLE IF YOU BRICK YOUR SYSTEM. Guide was followed as per here:

    Dell Inspiron 15R N5110 Native Speedstep BIOS Modding - Notebooks - InsanelyMac Forum

    In our case, we have a Phoenix BIOS/Insyde bios hybrid UEFI system.
    GUID for our powermanagement (as per my investigation, others feel free to explore): F7731B4C-58A2-4DF4-8980-5645D39ECE58

    In this BIOS's case, there are three big files associated with this GUID: F7731B4C-58A2-4DF4-8980-5645D39ECE58_1_705, F7731B4C-58A2-4DF4-8980-5645D39ECE58_1_2630, and F7731B4C-58A2-4DF4-8980-5645D39ECE58_1_4553


    Guide calls for only modifying the largest one (F7731B4C-58A2-4DF4-8980-5645D39ECE58_1_2630, 21KB vs 20KB), but I went ahead and modded all three since I found the same piece of reference code in all three files: 75 08 0f ba e8 0f 89 44 24 30 (we hack what is in red)

    Code to disable lockbit: eb 08 0f ba e8 0f 89 44 24 30 (this is the correct hacked ID to disable MSR 0xE2 lock

    again, I replaced this on all 3 power management files with the hacked code since I found "75 08 0f ba e8 0f 89 44 24 30" in all three of those files

    If anybody with more experience can contribute, please go ahead.

    I have recompiled the bios, re-decompiled, re-disassmbled and checked to make sure the right values are in place, and they seem to be.

    Anyway, modded bios file (CD img, NOT windows executable) is found here:
    X220tablet_1.6_Modified.iso

    MD5 verify checksum: C0BD3841F71ACB16A282BA9BB7CFD377

    good luck, hope for the best!
     
    Raidriar, Nov 13, 2012
    #1