Mi5 Loss Of Lte Bands

Discussion in 'Xiaomi Mi 5' started by GreasyMonkey1960, Aug 26, 2016.

  1. GreasyMonkey1960

    Aug 26, 2016
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    2G/3G/4G RAN Consultant
    Madrid/Manila
    Hi All,

    I am using a Mi5 Pro 128/4GB version, rooted with SuperSU, running MIUI8, version 6.8.18 ROM from this site, and am currently chasing a problem that has occurred after the phone did an "uncommanded restart", and since then have lost all LTE bands.

    Prior to this event I had LTE2100 and LTE2600, working on the correct bands/freqs, confirmed on Network Signal Guru tools.

    In the hope of restoring the bands I have tried swapping SIM's (other operators with known LTE coverage), single SIM slot, swapped SIM slots, check settings (yes, LTE preferred), without any progress.

    Further checks have been to do a complete TWRP wipe clean, re-install the OS (MIUI8) and all settings from scratch, checking for obvious problems in the settings of NVRAM 441, 1877, 6828, 6829 and a couple of others related to GSM/WCDMA/LTE operation and thus far, no success.

    IEMI values are correct, and the phone works fine on GSM and WCDMA.

    Does anyone have any other ideas as to what may cause this behaviour?

    Does anyone have a "clean-copy" of the .qcn file for the NVRAM from a Mi5 Pro, 128/4GB version which they could share with me (with "dummy" IMEI values) for me to patch in and try to eliminate this software package?

    Best Regards,
    GreasyMonkey.
     
  2. Cecco

    CeccoMembers

    Apr 1, 2016
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    do you have a backup of your efs partition, i think that this files are different for every phone and you must use yours
     
  3. GreasyMonkey1960

    Aug 26, 2016
    169
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    55
    Male
    2G/3G/4G RAN Consultant
    Madrid/Manila
    #3GreasyMonkey1960,Aug 26, 2016
    Last edited: Aug 28, 2016
    Hi, Not one that is able to be loaded - for some reason it was corrupted on the upload or attempted download, using QPST / QXDM tools.

    The only difference should be the IMEI, MEID and other device specific settings such as WLAN and Bluetooth MAC addresses.

    Other than the device-specific parameters, the settings for all the modem values should be identical.

    I have the required tools and information for identifying the differences, and changing them.

    Anyway, I have ordered another phone from the same source in EU, and will take a copy from that one when it arrives - then I will have a phone to use as a test-bed, since in real life I am a Network Performance & Optimisation Consultant.

    UPDATE:
    I have successfully recovered the 4G bands on the original phone, the problem appears to have been that during reboot, the NV values for NV946 and 2954 had changed to their maximum values, trying to turn on every band possible, the result being shutting down the 4G radio bands.

    Once I had done a complete wipe and reloaded the most recent global dev ROM, and without re-installing SuperSU and Network Signal Guru, the problem has cleared.

    Cheers.
     
  4. dambelboy

    dambelboyMembers

    Dec 9, 2016
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    Hi good day! Can you upload the nv values that changed and needed to be changed? Also having 4g problems with my mi5. Thanks in advance.

    Ps. Had already done multiple wipes and rom changes still nothing. Also tried changing nv values before but still no success.
     
  5. GreasyMonkey1960

    Aug 26, 2016
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    116
    55
    Male
    2G/3G/4G RAN Consultant
    Madrid/Manila
    Please read the prior post.
    The problem was NV946 and NV2954 had changed to their maximum values, but once set back to the original values, the phone restored LTE service.

    I do not have the values that I set it back to available at present, will be a week or two, as I am travelling international at present.
     
  6. ikebanat

    ikebanatMembers

    Dec 10, 2016
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    have same problem
     

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