Hi I have a Lumia 920,
Past weekend I too tried a numerous trick but finally accomplished and running windows 10 with OS build 10.0.14393.5
Really I don't remember which trick made it work but here I suggest to whatever I remember that I did.
First take a complete backup of your device and use WDRT (windows device recovery tool) to restore your firmware to a stock one.
As commented in most of the thread, you need not restore all your backup till windows 10 is installed and also avoid update of Extras & Info app from the Store. (I ensured that after every update that my phone did in the process, I would go to store and disable the automatic update and cancel every update process that the store was making to the apps)
Now check for updates and update your phone till it says the phone has the latest update installed. For me there were 3 updates available.
Then I used wpinternals to unlock my bootloader and enabled root access (without this set sideloading of registry editing tools were not possible for me). For sideloading using XAP application deployment tool, you may need a developer account and may need to use the "Windows Phone Developer Registration" application to developer unlock your mobile. For my Lumia 920 I used the "CustomPFD Registry Editor + Tweak" version 0.6 alpha. (I had downloaded numerous versions of customPFD, vcreg & roottool and tried to sideload everything one by one, but one xap file was a success, hence I don't remember for where I downloaded that file

)
Using that registry editor I swiped to Registry Tree -> HKLM -> System ->Platform ->DeviceTargetingInfo
from there I changed the values as follows. referred from
here
PhoneManufacturer value to "MicrosoftMDG"
PhoneManufacturerModelName to RM-1085_113025
PhoneHardwareVariant to RM-1085
PhoneModelName to Lumia 950
Now immediately after that use the WPinternal to disable the root and also restore the bootloader (FYI: Once I enabled the root and unlock bootloader after doing a WPRT recovery and the next update to CYAN didn't happened, I received an error after downloading the update as it can open the file (8007000d). Hence we are restoring the bootloader and root status.) Now I even opened the Windows Phone Developer Registration application in PC and unregistered from Developer status.
After this did a restart of the mobile phone and a new update started downloading. It turned out to be windows 10.0.10586.107. After the update I used the windows insider app and selected the fast ring and did a restart and the update downloaded the latest 10.0.14393.5.
Now my Lumia 920 is working fine so far without any issues.
I have mentioned the steps which I have taken as far as I remember. These may or may not work for others. But you may try at your own risk.
:good: