STEP 1 - find RootKeyHash and GPT.bin
locate your FFU file. If your phone bricked during Downgrade, you should have it in
c:\ProgramData\Microsoft\Packages\Products\rm-XXX...
or
c:\ProgramData\NOKIA\Packages\Products\rm-XXX...
It should be best if you have the Windows Phone Recovery Tool updated to 1.2.4
then go to the Microsoft / Windows Phone recovery folder (thor2.exe is there)
c:\Program Files (x86)\Microsoft Care Suite\Windows Phone Recovery Tool\
open up command line there, and make the dump in folder of your choice
Code:
thor2 -mode ffureader -dump_partitions -ffufile "RM9xx*.ffu" -filedir "c:\dump"
the log will display also the hash needed for you to find correct HEX file
Code:
Number of partitions found 28
RKH of SBL1: F771E62AF89994064F77CD3BC16829503BDF9A3D506D3FACECAEF3F808C868FD
RKH of UEFI: F771E62AF89994064F77CD3BC16829503BDF9A3D506D3FACECAEF3F808C868FD
also, the files are large, becaue the above step will make complete dump
you only need GPT.bin which is around 250 KB so get this file only
STEP 2. find the HEX file in the archive attached here
it is named with name starting as the RKH from previous step.
it is the first 40 bytes, so in the example
F771E62AF89994064F77CD3BC16829503BDF9A3D506D3FACECAEF3F808C868FD
is infact
F771E62AF89994064F77CD3BC16829503BDF9A3D.hex
STEP 3. try to get RED screen
Code:
thor2 -mode emergency -hexfile bin.hex -mbnfile gpt.bin -orig_gpt
the process above will not finish with success, as the provided GPT file is not only file needed to flash it. so I tried to flash it several times, reseting the phone ... etc., after 3-4 times, the phone vibrated, with red screen
STEP 4. flash your phone FFU image
Code:
thor2 -mode vpl -maxtransfersizekb 1 -vplfile "C:\ProgramData\Microsoft\Packages\Products\RM .... \* .vpl"
don't forget the -maxtransfersizekb flag because this flag perhaps was omitted in the Microsoft tool, making the flash procedure stop in the middle