root access - (SOLVED) How to recover data from Android ... /sdCard/ ... /Downloads on Xiaomi Mi5 MIUI8 (Android 6 Marshmallow)

UPDATE: 2018/06/27, bootloader implies wipe and it is a dead end for Data Recovery, mount as USB Mass Storage implies root to change settings, and for Mi5 or MIUI 8 this implies flashing ROM (dead end too as implies Data overwritten) so the only method I found is this (if the device is functional) then with the RAW partition dump recover files is easy

(LEGACY-post as is solved)

I have a problem I want to solve:

Notice: This is a specific problem, please try to advice on that matter (see complications at the bottom), any help and clarification will be very appreciated.

Fact:

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  I deleted by mistake files on path .. sdCard / .. / Downloads (internal memory)

  
  


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  Seconds after mistaken-deletion, I shut off the device, to prevent overwriting.

  
  

Specs: Smartphone Xiaomi Mi5 Miui 8 (Android 6 Marshmallow) Non-rooted Stock-recovery

WiP (workflow):

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  I notice about USB Mass Storage instead MTP (as key feature to connect device to PC) (and use some kind of recovery app like (Recuva or R-Studio (r-tt.com))

  
  


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  But I don't know how to activate that (Mass Storage) on my specific device and MIUI (Android version)

  
  

Another choice is create a image dump from custom recovery (TWRP) but how to install custom recovery... ... without changing the stock ROM, ... I saw unlocked bootloader is needed

Complications:

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  How to recover data from (internal sdCard, eMMc | UFS), without overwriting data.

  
  


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  How to root (if needed) without the changing of custom-ROM (if it is possible), on this specific device.

  
  


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  How to install custom recovery (bootloader unlocked is needed) to make a "raw image dump" exact byte-by-byte from the recovery ( isolated image dump, to work with IT Forensics tools)

  
  



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  Xiaomi Mi5 (how to root, methods, if it is needed), and how to install custom recovery, TWRP (bootloader unlocking etc)

  
  


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  Thanks in advance, first post here (a reader for years), I hope some people lead the way ^^, I want to learn.

  
  

Xiaomi Mi5 particularities: (more info-sources will be appreciated)

• root methods (without ROM-changing)



• TWRP recovery (stock ROM if possible) => create internal memory RAW image) to work with.


• Bootloader-unlock methods and process