XZ1 & XZ1 Compact: LB root & DRM backup/restore Bounty Thread - Sony Xperia XZ1 Guides, News, & Discussion

Bounty for locked bootloader root and/or DRM backup + restore for Sony Xperia XZ1 lineup: XZ1 and XZ1 Compact
Introduction
For years, Sony Xperia flagships have offered a great almost-stock Android experience and high build quality which makes them appealing to many. The main downside is rooting of Xperia devices using the official Sony method requires unlocking of the bootloader, and thus loss of TA partition and the DRM keys in it. You can NOT undo/recover these.
The effect is permanent loss of Sony proprietary features - those interested in exact details on what you lose can find years of info on Google - but too long didn't google: Audio quality and camera image quality are reduced, some camera features are lost (e.g. noise reduction/photo enhancement in low-light), screen enhancement features are lost (Bravia Engine modes: X-Reality and Super Vivid)
The latest Xperia flagship which could be rooted and DRM restored was the 2016 Xperia XZ - that's a model from over a year ago!
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What is bounty and how does it work?
Root bounties have been incredibly successful in creating traction from community members towards finding root methods in many brands of phones in the past.
Xperia devices running Android 4.x: exploits were used to keep the bootloader locked while rooting. Keeping bootloader locked while rooting became more difficult after Lollipop
Xperia devices running Android 5 Lollipop and Android 6 Marshmallow used the 2016 DirtyCow exploit to backup and restore TA partition instead so DRM features could be used after unlocking bootloader/rooting.
No 2017 Xperia devices and Xperia running Android 7 Nougat or higher have been successfully rooted while maintaining DRM features as of writing this post.
The Xperia XZ1 and XZ1 Compact will ship with Android 8 Oreo.
This thread was created because the only bounty thread for a 2017 model, the XZ Premium, has not gained much traction. With Xperia Standard and Compact flagship models traditionally having higher demand than the Xperia Premium variant, we can get more awareness and a higher reward with an XZ1 & XZ1 Compact bounty campaign.
Historically, the success in getting locked bootloader root or DRM backup for one Xperia flagship makes it significantly easier to achieve the same for the sibling model, and other Xperia devices (e.g. Xperia Z3/Z3 Compact bounty from 2014).
Bounty claim requirements:
In order to claim this bounty, refer to the following steps:
Be the first person to create or find a method in the latest available software release on the aforementioned devices to either (A) obtain root access without unlocking bootloader or compromising/affecting the TA partition in any way; or (B) root method that allows TA partition to be backed up before root process AND restored after root process; or (C) an entirely different way that allows TA partition and DRM features to be remain usable by retention, restoration or other, after the device has been rooted.
Give proof of point #1 by posting an adequate quantity of screenshots to illustrate it, together with step by step instructions, in a fashion such that everyone can follow them and reproduce the exploit;
Wait for at least 10% of pledgers (fastest quorum achieved between per capita and per pecunia criteria*) to give confirmation about the method functionality;
Claim your bounty via PM from pledgers. This first post will also be updated with your username.
*i.e. the fastest between 10% of the number of people and 10% of the amount of money pledged as bounty.
Like other bounty threads, this first post will be updated with the username of the successful bounty claimer upon verification of the root/DRM preservation method.
Total pledge: $856
Updated Nov 7, 2017
Note: Payment will be processed between each member and the bounty collector via PM on an individual basis. Original amounts in non-USD currency listed in brackets, exchange rates may vary for these pledges.
List of pledges:
Corgism - $18 (EUR 15)
[*]karrouma - $15 (Withdrawn)
kistigun - $18 (EUR 15)
CM17X - $30
Klaus N. - $35 (EUR 30)
mhaha - $10
wk205 - $35 (EUR 30)
inteltecra1700 - $20
kpgc10kai - $40
Dioptas - $40
ChronoReverse - $32 (CAD 40)
SockPants - $10
williamgrant - $20
smorgar - $47 (EUR 40)
blackknightavalon - $20
pbarrette - $20
WaxysDargle - $20
xherbert - $20
Tagilso - $18 (EUR 15)
Belyavin - $10
andacro - $40
KirKone - $47 (EUR 40)
f1^ter - $35 (EUR 30)
Nickcer - $10
Space_pilot - $40
JobAnsonMcKee - $50
silestanix - $13 (GBP 10)
marcelcerdan13 - $58 (EUR 50)
Shamoy - $50
WhipeeDip - $10
Braindeadz - $40 (EUR 35)
Rules of this bounty thread:
- Before posting in this thread, please check to the list below if your post will be acceptable. If it is not part of this list, your post will be reported and you may risk getting an infraction as per forum moderators.
- Please note you may not make any specific restrictions or requirements that aren't listed in the OP. By making a post with your contribution price you are agreeing to paying out based on all terms listed in OP only and nowhere else.
- Please be advised that if Sony is to release an official method of rooting without unlocking the bootloader or restoring DRM/TA partitions lost by officially unlocking the bootloader (extremely unlikely but must be accounted for) prior to any member of XDA's submission, this bounty automatically becomes invalidated.
- Please do not PM a pledge, for it will not be counted.
List of acceptable posts:
- New bounty submission or increase of current bounty;
- Questions or assistance in development of a root, recovery, or bootloader unlock method;
- Questions and answers regarding bootloaders on this device;
- Questions and answers regarding the nature of lockdown on this device;
- Questions and answers regarding kernel and bootloader-related exploits;
- Any kind of updates about unfinished or still work-in-progress methods that would at the moment of posting be unfit for fulfilling the bounty;
- Bounty's fulfillment.
Special thanks
To users A) Pyres for the inspiration from your 2014 Z3/Z3 Compact bounty thread. Used some of your text with rephrasing for shorter length/clearer message. and B) leijonasisu for kicking off the XZ Premium bounty, also borrowed a phrase or two from your thread.

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i will be there with 15$ , moved from xz premium to xz1

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I'm in for €15,-

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I'm in. USD $30
Coming from XZ Premium forum.

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Ok, you can add me with € 30,-

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Chipping in $10

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Count on me for 30€. In my case it is just about making RSAP work. That's it. Not more and not less.

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I'll give $20

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I will add $40.

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I'm in with $40

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$40 (CAD) for XZ1 Compact G8342

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US$ 10 for G8441 . Offtopic: I'm also interested in how to set a custom battery charge limit. Battery Care does something like this on this phone, and there are root apps available that turn off charging at a certain %.

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I'm in USD 20 for G8441!

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Thread (Temporarily) closed
Thread re-opened, thread cleaned.
Do not feed the trolls!

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Put me up for 10€

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$20 for G8441 (just got mine today)

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I'm in for 20 USD on the XZ1c.

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i'm in for $20 on XZ1C

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In
$20 for XZ1 - G8342

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1 off topic post removed.