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[ROM][UNOFFICIAL] LineageOS 14.1 for Lenovo Tab 3 8/TB3-850F

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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
LineageOS 14.1 Port ROM
Lenovo Tab 3 8"/TB3-850F


•WARNING:
You are installing this custom Android ROM at your own discretion and risk. If you are unclear on anything, please stop and do some research before proceeding further. This is not a Q & A thread, so please post comments on topic with subject matter relating directly to this ROM. I will not be held responsible for devices which become bricked or damaged as a result of installing this ROM. You are encouraged to read and re-read the OP prior to installing this ROM on your device. Please visit this thread for now to make general inquiries about this ROM or about any other questions or issues you may have regarding the 850F. Either myself or XDA Senior Member @pndwal, who is very knowledgeable about this device and Android in general, will try to address your questions. https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786 User input and feedback are essential in making improvements, fixing bugs, and in helping development for this device to continue to evolve.
Any skilled devs interested in contributing in any way to development for the 860F, please use the above thread to contact @pndwal and coordinate with him in that area.

I am not a developer, nor did I contribute to the porting of this LineageOS 14.1 custom ROM for the TB3-850F. I merely packaged up the files, added GApps Pico, made a few minor tweaks, and created a TWRP flashable zip installer for this ROM. Please do not request updates or make ETA type inquiries on this thread. Whether or not this ROM will be maintained is still up in the air. Please give any and all credit to the individuals I have listed below under Mentions & Credits.

LineageOS 14.1 is a free, aftermarket distribution of Android 7.1.2 Nougat, which is designed to increase performance and reliability over stock Android for your device.

LineageOS is based on the Android Open Source Project with extra contributions from many individuals within the Android community. Although this particular LineageOS build does have GApps Pico preinstalled, it can be used without any need to have any Google application installed. LineageOS does still include various hardware specific code, which is nonetheless slowly being open-sourced anyway.

SOURCES:
LineageOS Source Code: https://github.com/LineageOS

Kernel Source Code: https://support.lenovo.com/us/en/downloads/ds112711

LineageOS Gerrit Code Review: https://review.lineageos.org/q/status:open

FEATURES & SPECS:
•LineageOS Version: 14.1
•Android Base Version: 7.1.2_r8 Nougat
•Build ID: N2G470
•SDK Version: 25
•Build Date: May 15, 2017
•Security Patch Level: May 5, 2017
•Kernel Version: 3.18.19 (mods by @wezroot2k)
•LineageOS API Level: Guava (7)
•GApps Pico Pre-installed
•Insecure Boot Image Support
•Force Encryption Disabled (Opt-Encrypt)
•AVB/dm-verity Disabled
•Fully Deodexed
•Fully Zip-aligned
•User Opt Root or Non-Root
•Status: Unofficial/Stable

WORKING:
•Booting
•WiFi
•Bluetooth
•Graphics/Video Playback
•Audio
•GPS/Location Services
•GApps
•Magisk Universal Systemless Interface

BUGS:
I am presently working on Settings UI to omit the mobile networks/telephony entries. These are present because this ROM was originally a smartphone port. Otherwise, please feel free to submit a proper bug report or, at a minimum, a clear description of the bug or instability, including screenshots if possible.
A bug has been reported for apps that require superuser permissions (Greenify, root file managers, etc), and I have determined that installing the latest Magisk systemless root will alleviate that bug.
Upon initial boot, during setup, you may experience an issue with Setup Wizard force closing. I have posted a quick workaround for this below under the Installation Instructions heading.

REQUIREMENTS:
You need an unlocked bootloader and TWRP custom recovery installed. If you need help with either of these topics, please visit this thread for guidance: https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786

INSTALLATION INSTRUCTIONS:
1. Download the ROM zip from the below download link and save it to your device storage...
2. Boot your device into TWRP recovery mode...
3. Wipe Data, Cache & Dalvik/ART (my installer automatically formats the /system partition)...
4. Select Install, navigate to saved location of the ROM zip, select it and swipe the action bar to begin installation...
5. Reboot system (installation will take around three minutes).

*Because this ROM is fully deodexed, first boot can take several minutes to complete while the Dalvik/ART directories are being written for the first time. The second and subsequent boot times will be much faster. Also, on first boot, select your language then choose SKIP on the Insert SIM Card screen. You will then be prompted to set up your device as new or copy data from another device as part of setup. At this stage, if the Setup Wizard force closes, swipe down from the top of the screen to access Quick Settings and go ahead and connect to a WLAN/WiFi network. Now, go back to the previous screen and Setup Wizard should function normally and allow you to proceed with setup of your device. I am presently working on removing SIM/Mobile Network settings on this device, so hopefully this will be fixed soon, and a true WiFi-only tablet port will be yielded.

**As mentioned supra, this ROM is packaged with GApps Pico, which provides the bare bones minimum for Google Play functionality. If you want a GApps package other than the one preinstalled, visit https://opengapps.org/, choose ARM64, Android 7.1, and select your preferred package. Simply install the GApps package after Step 4 above. If you want root, visit the official Magisk release & announcement thread here https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445, and download the latest Magisk Manager apk. Install the apk, go to Developer Options and enable Apps & ADB in the root options menu. Open Magisk Manager, select Install, pick the direct install option, and systemless root will be installed via patched boot image. Reboot and systemless root should be properly installed & stable. Be sure and hit the Thanks button on @topjohnwu's thread if you use Magisk.


MENTIONS & CREDITS:
This port was made possible by a number of individuals both here at XDA and abroad:
- Credit goes to 4PDA (Russian Development site) member chipa76 for the original TB3-850M port, and to 4PDA member al_rus for his contributions to, and for posting that port.
- Credit and thanks for the breakthrough moment for TB3-850F users must go to XDA member @wezroot2k who, after others tried for many months, was finally able to stabilise this ROM for our device by recompiling the ported boot image with TB3-850F stock kernel. Also, he has worked on tweaks to streamline the ROM for TB3-850F.
- TWRP flashable ROM package as well as some tweaks to streamline the ROM for TB3-850F have been made by the OP, @AeonFlux1603, who will continue to work on a few further improvements, insomuch as spare time will allow
- Thanks to XDA Senior Member @pndwal for his dedication to this device and for passing on suggestions from the 4PDA Devs regarding the adopted method of stabilising ROM for TB3-850F.
- Last but not least, thanks and credit goes to the entire LineageOS Dev Team for making this custom aftermarket distribution of Android possible for low-grade, mid-grade & flagship devices alike.

DOWNLOAD LINK:
LineageOS 14.1 for TB3-850F: https://drive.google.com/file/d/1bbpwyvP_S4k1PJaLa6RN3dFDF8UYEcNj/view
 
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
@wezroot2k, I just wrote up a full thread for the ROM and hit the post button. It posted the first paragraph and that's it. Two hours of work and my XDA Labs app deleted everything.
 

wezroot2k

Senior Member
Sep 12, 2017
100
78
•WARNING:
You are installing this custom Android ROM at your own discretion and risk. If you are unclear on anything, please stop and do some research before proceeding further. This is not a Q & A thread, so please post comments on topic with subject matter relating directly to this ROM. I will not be held responsible for devices which become bricked or damaged as a result of installing this ROM. You are encouraged to read and re-read the OP prior to installing this ROM on your device.

•LineageOS
I wonder why that is?
I think you should talk to PW

---------- Post added at 08:49 AM ---------- Previous post was at 08:46 AM ----------

@wezroot2k, I just wrote up a full thread for the ROM and hit the post button. It posted the first paragraph and that's it. Two hours of work and my XDA Labs app deleted everything.

Y would the app do that?
Maybe you would have to create the thread from a PC.
 
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
I wonder why that is?
I think you should talk to PW

---------- Post added at 08:49 AM ---------- Previous post was at 08:46 AM ----------



Y would the app do that?
Maybe you would have to create the thread from a PC.
I'll redo the work in the morning. That's got me as aggravated as you can get. I posted full sources, credits, instructions, specs, etc. All got erased.
 

wezroot2k

Senior Member
Sep 12, 2017
100
78
Oh. Did I do something wrong?
No man,just saying PW might know why the app would just post part of the thread and not the full thing.

---------- Post added at 09:08 AM ---------- Previous post was at 09:07 AM ----------

I'll redo the work in the morning. That's got me as aggravated as you can get. I posted full sources, credits, instructions, specs, etc. All got erased.
Sorry to hear about that man.
 

AeonFlux1603

Senior Member
Feb 1, 2019
188
164
App could've timed out. Similar to chrome. I copy/select all before confirming just incase (with pretty much every hefty message I write)
Oh ok. Between that, copy/pasting and backspacing a lot, that's likely what happened. Working on reworking the thread now. Thanks for the insight. I'm editing in a little at a time to play it safe.
 
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pndwal

Senior Member
Oh ok. Between that, copy/pasting and backspacing a lot, that's likely what happened. Working on reworking the thread now. Thanks for the insight. I'm editing in a little at a time to play it safe.
Just read this new thread! Well done n many thanks.

As I explained in other thread (not sure if you understood properly - please read it carefully again to avoid heartache), XDA Labs does have a serious fault. Simply put, posts are shortened to a point where '*' symbol occurs, and because copying and pasting often swaps spaces (between words) for this symbol, the post gets truncated and your efforts are lost!

I said:
Frustrating to lose all that typing :( . Sorry to hear that.

Beware of accidently hitting 'backspace' after highlighting text!

***Also, please be aware (if you use it,) that XDA Labs app is flawed, and will often unexpectedly truncate your post when sending. This usually happens when you've copied and pasted info - you'll find '*' substituted for spaces in places, and the first one will be near the point the post is truncated. I always highlight and copy complete post before sending, and if I lose text I repost it from browser, which doesn't have these issues.

Sounds like @Hemphiz and others have all learned the hard way as I did, and take the same precautions.

Hope it helps in future, and bravo for your efforts and hard work for us! Regards, PW
 
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wezroot2k

Senior Member
Sep 12, 2017
100
78
:highfive: Hey AF just read the thread and I love and thanks for the kudos and well done.

I have installed your LOS 14.1 packages and must say it is stable very smooth and love your installer :highfive: I am using it right now and loving it:cowboy:

Also I did notice I minor thing and this for all user of this rom ,this is maybe not the ROM port fault but maybe the specific app bug or compatibility issue. I notice that the Greenify app does not do well with the default SU add-on of this ROM Greenify just does not load. Keeps crashing at getting su root access screen, but it does work with other root method so maybe something to look into.
Also I think you should edit the build.prop values for things like model number should be changed to 850F and not 850m and so fourth.
I have a build.prop file I can send you to look at.
Otherwise everything else is good
Excellent work AF:cowboy::cowboy:
 
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
Just read this new thread! Well done n many thanks.

As I explained in other thread (not sure if you understood properly - please read it carefully again to avoid heartache), XDA Labs does have a serious fault. Simply put, posts are shortened to a point where '*' symbol occurs, and because copying and pasting often swaps spaces (between words) for this symbol, the post gets truncated and your efforts are lost!

I said:


Sounds like @Hemphiz and others have all learned the hard way as I did, and take the same precautions.

Hope it helps in future, and bravo for your efforts and hard work for us! Regards, PW
Yeah. And I did take your advice, but instead of using my notebook, I used Labs again, except this time I posted every time a section was complete, fully copying all my text before hitting the post button. Thank you for the warnings and info. I will know in the future.
 
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
:highfive: Hey AF just read the thread and I love and thanks for the kudos and well done.

I have installed your LOS 14.1 packages and must say it is stable very smooth and love your installer :highfive: I am using it right now and loving it:cowboy:

Also I did notice I minor thing and this for all user of this rom ,this is maybe not the ROM port fault but maybe the specific app bug or compatibility issue. I notice that the Greenify app does not do well with the default SU add-on of this ROM Greenify just does not load. Keeps crashing at getting su root access screen, but it does work with other root method so maybe something to look into.
Also I think you should edit the build.prop values for things like model number should be changed to 850F and not 850m and so fourth.
I have a build.prop file I can send you to look at.
Otherwise everything else is good
Excellent work AF:cowboy::cowboy:
That's good to know on Greenify. Flashing a Magisk v18.1 systemless root installer zip via TWRP would likely fix the issue. I have noticed a similar problem using MiXplorer in root file manager mode. The problem like you said is likely the LOS 14.1 su_addon.
Glad you're loving it my friend. After working so hard to help make it possible, you are deserving indeed.
 
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pndwal

Senior Member
That's good to know on Greenify. Flashing a Magisk v18.1 systemless root installer zip via TWRP would likely fix the issue. I have noticed a similar problem using MiXplorer in root file manager mode. The problem like you said is likely the LOS 14.1 su_addon.
Glad you're loving it my friend. After working so hard to help make it possible, you are deserving indeed.
Not sure if you're using adoptive storage, or where MiXplorer (or Greenify) loads by default, but generally apps requiring root access lose functionality or won't load at all if installed on SD storage.

I use ES File explorer which installs to SD by default, but it must be moved to internal to enable its inbuilt root explorer, otherwise its root test fails and root explorer toggles off.

This just may be your problem too. - Pays to check SuperUser enabled apps in manager, and ensure each of these is on internal storage. PW.

---------- Post added at 09:49 AM ---------- Previous post was at 09:42 AM ----------

Y would the app do that?
Maybe you would have to create the thread from a PC.
Yet the Labs app does this often :( . I've explained in my last post on page 1. PW

---------- Post added at 09:57 AM ---------- Previous post was at 09:49 AM ----------

...I notice that the Greenify app does not do well with the default SU add-on of this ROM Greenify just does not load. Keeps crashing at getting su root access screen
My post to AF above re storage may help here, but could be SU used as you say. PW
 

AeonFlux1603

Senior Member
Feb 1, 2019
188
164
Not sure if you're using adoptive storage, or where MiXplorer (or Greenify) loads by default, but generally apps requiring root access lose functionality or won't load at all if installed on SD storage.

I use ES File explorer which installs to SD by default, but it must be moved to internal to enable its inbuilt root explorer, otherwise its root test fails and root explorer toggles off.

This just may be your problem too. - Pays to check SuperUser enabled apps in manager, and ensure each of these is on internal storage. PW.

---------- Post added at 09:49 AM ---------- Previous post was at 09:42 AM ----------


Yet the Labs app does this often :( . I've explained in my last post on page 1. PW

---------- Post added at 09:57 AM ---------- Previous post was at 09:49 AM ----------


My post to AF above re storage may help here, but could be SU used as you say. PW
I'm not running adoptive storage now. I had previously tried it to ensure operability. But, you actually just helped me troubleshoot a problem I was having on my LG G4 with root. It was due to adoptive storage. Haha. Man PW you know your Android for sure. Thanks.
So on our 850F I'm going to try Magisk or phh-superuser systemless root (or maybe SuperSU v2.82-SR5) to see if that fixes root access of the OS.
Also, I'll be posting the stock 6.0 firmware this evening sometime, with fastboot instructions. I was wrong about it being the most current build. It is actually one of the initial builds that shipped with the 850F in mid to late April, 2016. Hard to believe this device is nearly three years old now. So, once installed, the user will be prompted to install a series of OTA updates subsequent to initial boot and setup.
 
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pndwal

Senior Member
App could've timed out. Similar to chrome. I copy/select all before confirming just incase (with pretty much every hefty message I write)
I've found even if it times out, or can't connect when sending, things are generally handled properly by Labs app, a message appears that 'send failed', and text is all still there allowing further attempts.

However, the space-substituted-for-*-symbol problem (when copying and pasting) will truncate the post and successful send in one operation. This means a large portion of text is often lost and irretrievable. (Also, the * symbol still shows as a space while editing, so one doesn't realise that the space has been substituted until its too late.)

Great advice to copy all before sending. PW

---------- Post added at 06:17 AM ---------- Previous post was at 05:22 AM ----------

@wezroot2k, @AeonFlux1603

TB3-850F users are privileged, blessed, ecstatic, proud, happy and very thankful to have two budding (though clearly possessed of valuable experience and practical knowledge) developers on board the Good Ship TB3-850F, and its been a long time coming!

Thank you both especially for Stable and Virtually Bug Free Port to LOS14.1 for TB3-850F, as well as for other valuable resources we are gaining - including this new thread for our brand new Lineage Operating System!

Your sincere expressions of thanks / praise for helpful posts are also much appreciated.

Just a small heads-up (and sorry to spell it out) - Please don't neglect the 'thanks' (thumb up) button when a post is useful, or a sincere attempt to help is made. This is kind of the expected / default expression of thanks around here, and is possibly the most sincere form of flattery as it also elevates a members XDA profile. It's a simple and immediate way to say 'thanks', and often makes further comment unnecessary. (Incidentally, thanked posts are indexed, and are often perused for helpful information.)

Many thanks, and loving your work! PW :good::good::good::good::good:
 
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
It looks like I have the Settings UI ironed out, with all mobile networks/SIM options removed in the Settings menu. I'm going to to repackage the Settings apk, implement it back into the /system directory and see if it works. If so I will update the OP with a new build.
Also, Magisk systemless root appears to be a fully stable root protocol on this LOS build. . Oddly, after flashing the Magisk v18.1 systemless root installer zip with TWRP, the Magisk Manager app doesn't appear upon reboot. But, once you manually install Magisk Manager v7.0.0 (185), root shows as properly installed and up to date. Thus far, I have noticed no instabilities or bugs with Magisk.
So, the recommended method of installing Magisk systemless root on this ROM is to first install the latest Magisk Manager v7.0.0 (185) apk, select Install from the app, and choose the direct install option. Reboot and Magisk v18.1 systemless root should be properly installed and stable. Go here to visit the official Magisk release and announcement thread https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445 where you can download the latest Magisk Manager apk and systemless root installer zip. Be sure and thank @topjohnwu if you use Magisk.
 
Last edited:
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AeonFlux1603

Senior Member
Feb 1, 2019
188
164
Update on Settings UI. After repackaging the Settings apk and framework-res.apk, I am experiencing force closes every time Settings is opened. It is probably something as simple as an encoding issue or an error during repacking but I'll keep progress posted.
 

AeonFlux1603

Senior Member
Feb 1, 2019
188
164
Update on the Settings UI. I now realize that my issues were due to my failure to properly encode my edits of the relevant .XML files with UTF-8 encoding prior to repackaging. As I may have mentioned previously, I am interested in bringing this port up to date with the latest upstream sources. So my next build release will hopefully include current LOS sources and have the Settings UI ironed out. While progress is not nearly as quick as I'd like, I am working on it.
 
Last edited:

AeonFlux1603

Senior Member
Feb 1, 2019
188
164
I don't know about you guys as far as audio preferences, but I was really partial to the stock Dolby Atmos app that ships preinstalled on this device. I done a little testing to find a comparable audio setup. There is a Magisk Module titled Collective Dolby Atmos (ZTE Axon 7) v1.8 (2.2.1.7_r1), last updated on January 15, 2019, that works great on this ROM, with nearly exactly the same features and UI as the stock Lenovo version of Dolby Atmos. To install it, of course, you can simply download the Module and install it via Magisk Manager or via TWRP. There are several different Dolby ports available. This is the official support and release thread: https://forum.xda-developers.com/android/apps-games/soundmod-axon-7-dolby-atmos-t3412342
 
Last edited:
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pndwal

Senior Member
I don't know about you guys as far as audio preferences, but I was really partial to the stock Dolby Atmos app that ships preinstalled on this device. I done a little testing to find a comparable audio setup. There is a Magisk Module titled Collective Dolby Atmos (ZTE Axon 7) v1.8 (2.2.1.7_r1), last updated on January 15, 2019, that works great on this ROM, with nearly exactly the same features and UI as the stock Lenovo version of Dolby Atmos. To install it, of course, you can simply download the Module and install it via Magisk Manager or via TWRP. There are several different Dolby ports available. This is the official support and release thread: https://forum.xda-developers.com/android/apps-games/soundmod-axon-7-dolby-atmos-t3412342
Quite like ViPER4AndroidFX ( @ahrion, @Zackptg5) Magisk module. I think it auto-installs AML - Audio Modification Library - Magisk module (by @ahrion, @Zackptg5) also. (Used to anyway.)

AML currently supports all these mods too, so its a smörgåsbord:
- AM3D
- AudioWizard
- V4AFX
- V4AXhifi
- Dolby Atmos (ahrion's ports)
- Dolby Atmos Axon 7 Oreo (guitardedhero's port)
-Dolby Digital Plus
-Bang&Olufsen ICEPower (only tested ainur version)
- Arkamys (only tested ainur version)
- Dirac (only tested ainur version)
- Dirac Hexagon (only tested ainur version)
- JamesDSP
- MaxX Audio 3
- Audio Compatibility Patch (formerly universal deep_buffer remover)
- Ainur Sauron
- SquareSound
- DTS Wizard
- Sony Xperia Z2 Sound System

I see Dolby Atmos Axon 7 Oreo in this list too. Haven't tried it, but I know guitardedhero's a bit of a genius with these mods. PW.
 
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    LineageOS 14.1 Port ROM
    Lenovo Tab 3 8"/TB3-850F


    •WARNING:
    You are installing this custom Android ROM at your own discretion and risk. If you are unclear on anything, please stop and do some research before proceeding further. This is not a Q & A thread, so please post comments on topic with subject matter relating directly to this ROM. I will not be held responsible for devices which become bricked or damaged as a result of installing this ROM. You are encouraged to read and re-read the OP prior to installing this ROM on your device. Please visit this thread for now to make general inquiries about this ROM or about any other questions or issues you may have regarding the 850F. Either myself or XDA Senior Member @pndwal, who is very knowledgeable about this device and Android in general, will try to address your questions. https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786 User input and feedback are essential in making improvements, fixing bugs, and in helping development for this device to continue to evolve.
    Any skilled devs interested in contributing in any way to development for the 860F, please use the above thread to contact @pndwal and coordinate with him in that area.

    I am not a developer, nor did I contribute to the porting of this LineageOS 14.1 custom ROM for the TB3-850F. I merely packaged up the files, added GApps Pico, made a few minor tweaks, and created a TWRP flashable zip installer for this ROM. Please do not request updates or make ETA type inquiries on this thread. Whether or not this ROM will be maintained is still up in the air. Please give any and all credit to the individuals I have listed below under Mentions & Credits.

    LineageOS 14.1 is a free, aftermarket distribution of Android 7.1.2 Nougat, which is designed to increase performance and reliability over stock Android for your device.

    LineageOS is based on the Android Open Source Project with extra contributions from many individuals within the Android community. Although this particular LineageOS build does have GApps Pico preinstalled, it can be used without any need to have any Google application installed. LineageOS does still include various hardware specific code, which is nonetheless slowly being open-sourced anyway.

    SOURCES:
    LineageOS Source Code: https://github.com/LineageOS

    Kernel Source Code: https://support.lenovo.com/us/en/downloads/ds112711

    LineageOS Gerrit Code Review: https://review.lineageos.org/q/status:open

    FEATURES & SPECS:
    •LineageOS Version: 14.1
    •Android Base Version: 7.1.2_r8 Nougat
    •Build ID: N2G470
    •SDK Version: 25
    •Build Date: May 15, 2017
    •Security Patch Level: May 5, 2017
    •Kernel Version: 3.18.19 (mods by @wezroot2k)
    •LineageOS API Level: Guava (7)
    •GApps Pico Pre-installed
    •Insecure Boot Image Support
    •Force Encryption Disabled (Opt-Encrypt)
    •AVB/dm-verity Disabled
    •Fully Deodexed
    •Fully Zip-aligned
    •User Opt Root or Non-Root
    •Status: Unofficial/Stable

    WORKING:
    •Booting
    •WiFi
    •Bluetooth
    •Graphics/Video Playback
    •Audio
    •GPS/Location Services
    •GApps
    •Magisk Universal Systemless Interface

    BUGS:
    I am presently working on Settings UI to omit the mobile networks/telephony entries. These are present because this ROM was originally a smartphone port. Otherwise, please feel free to submit a proper bug report or, at a minimum, a clear description of the bug or instability, including screenshots if possible.
    A bug has been reported for apps that require superuser permissions (Greenify, root file managers, etc), and I have determined that installing the latest Magisk systemless root will alleviate that bug.
    Upon initial boot, during setup, you may experience an issue with Setup Wizard force closing. I have posted a quick workaround for this below under the Installation Instructions heading.

    REQUIREMENTS:
    You need an unlocked bootloader and TWRP custom recovery installed. If you need help with either of these topics, please visit this thread for guidance: https://forum.xda-developers.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786

    INSTALLATION INSTRUCTIONS:
    1. Download the ROM zip from the below download link and save it to your device storage...
    2. Boot your device into TWRP recovery mode...
    3. Wipe Data, Cache & Dalvik/ART (my installer automatically formats the /system partition)...
    4. Select Install, navigate to saved location of the ROM zip, select it and swipe the action bar to begin installation...
    5. Reboot system (installation will take around three minutes).

    *Because this ROM is fully deodexed, first boot can take several minutes to complete while the Dalvik/ART directories are being written for the first time. The second and subsequent boot times will be much faster. Also, on first boot, select your language then choose SKIP on the Insert SIM Card screen. You will then be prompted to set up your device as new or copy data from another device as part of setup. At this stage, if the Setup Wizard force closes, swipe down from the top of the screen to access Quick Settings and go ahead and connect to a WLAN/WiFi network. Now, go back to the previous screen and Setup Wizard should function normally and allow you to proceed with setup of your device. I am presently working on removing SIM/Mobile Network settings on this device, so hopefully this will be fixed soon, and a true WiFi-only tablet port will be yielded.

    **As mentioned supra, this ROM is packaged with GApps Pico, which provides the bare bones minimum for Google Play functionality. If you want a GApps package other than the one preinstalled, visit https://opengapps.org/, choose ARM64, Android 7.1, and select your preferred package. Simply install the GApps package after Step 4 above. If you want root, visit the official Magisk release & announcement thread here https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445, and download the latest Magisk Manager apk. Install the apk, go to Developer Options and enable Apps & ADB in the root options menu. Open Magisk Manager, select Install, pick the direct install option, and systemless root will be installed via patched boot image. Reboot and systemless root should be properly installed & stable. Be sure and hit the Thanks button on @topjohnwu's thread if you use Magisk.


    MENTIONS & CREDITS:
    This port was made possible by a number of individuals both here at XDA and abroad:
    - Credit goes to 4PDA (Russian Development site) member chipa76 for the original TB3-850M port, and to 4PDA member al_rus for his contributions to, and for posting that port.
    - Credit and thanks for the breakthrough moment for TB3-850F users must go to XDA member @wezroot2k who, after others tried for many months, was finally able to stabilise this ROM for our device by recompiling the ported boot image with TB3-850F stock kernel. Also, he has worked on tweaks to streamline the ROM for TB3-850F.
    - TWRP flashable ROM package as well as some tweaks to streamline the ROM for TB3-850F have been made by the OP, @AeonFlux1603, who will continue to work on a few further improvements, insomuch as spare time will allow
    - Thanks to XDA Senior Member @pndwal for his dedication to this device and for passing on suggestions from the 4PDA Devs regarding the adopted method of stabilising ROM for TB3-850F.
    - Last but not least, thanks and credit goes to the entire LineageOS Dev Team for making this custom aftermarket distribution of Android possible for low-grade, mid-grade & flagship devices alike.

    DOWNLOAD LINK:
    LineageOS 14.1 for TB3-850F: https://drive.google.com/file/d/1bbpwyvP_S4k1PJaLa6RN3dFDF8UYEcNj/view
    3
    Update on the Settings UI. I now realize that my issues were due to my failure to properly encode my edits of the relevant .XML files with UTF-8 encoding prior to repackaging. As I may have mentioned previously, I am interested in bringing this port up to date with the latest upstream sources. So my next build release will hopefully include current LOS sources and have the Settings UI ironed out. While progress is not nearly as quick as I'd like, I am working on it.
    3
    App could've timed out. Similar to chrome. I copy/select all before confirming just incase (with pretty much every hefty message I write)
    I've found even if it times out, or can't connect when sending, things are generally handled properly by Labs app, a message appears that 'send failed', and text is all still there allowing further attempts.

    However, the space-substituted-for-*-symbol problem (when copying and pasting) will truncate the post and successful send in one operation. This means a large portion of text is often lost and irretrievable. (Also, the * symbol still shows as a space while editing, so one doesn't realise that the space has been substituted until its too late.)

    Great advice to copy all before sending. PW

    ---------- Post added at 06:17 AM ---------- Previous post was at 05:22 AM ----------

    @wezroot2k, @AeonFlux1603

    TB3-850F users are privileged, blessed, ecstatic, proud, happy and very thankful to have two budding (though clearly possessed of valuable experience and practical knowledge) developers on board the Good Ship TB3-850F, and its been a long time coming!

    Thank you both especially for Stable and Virtually Bug Free Port to LOS14.1 for TB3-850F, as well as for other valuable resources we are gaining - including this new thread for our brand new Lineage Operating System!

    Your sincere expressions of thanks / praise for helpful posts are also much appreciated.

    Just a small heads-up (and sorry to spell it out) - Please don't neglect the 'thanks' (thumb up) button when a post is useful, or a sincere attempt to help is made. This is kind of the expected / default expression of thanks around here, and is possibly the most sincere form of flattery as it also elevates a members XDA profile. It's a simple and immediate way to say 'thanks', and often makes further comment unnecessary. (Incidentally, thanked posts are indexed, and are often perused for helpful information.)

    Many thanks, and loving your work! PW :good::good::good::good::good:
    3
    I still saw some mention about bugs, but I'm not understand what they are because of Google translate. Besides, Can I flash this on 850M? I don't have intention of using any SIM-related service.
    Yes, I read about LOS14.1 TB3-850M bugs on 4pda too, but I think most are gone in ver. 3. I was just wondering what bugs you have found remaining with latest build on 850M.

    Not a good idea to flash on 850M as kernel is different, which is why we had bootloops and instability before we got boot.img for 850F, so I think you will have similar problems using ROM with 850F boot.img on 850M.

    However, if you really want to try this ROM, you could extract boot.img from TB3-850M LOS14.1 ROM, then flash TB3-850F ROM immediately followed by boot.img from 850M.
    About the Zirene, I also see that on the thread and looks like the app cannot work reliably on android version bigger than 6, the dev also said that Zirene is too old.
    I see. That may be the problem then. PW
    3
    Hey there.
    Thanks a lot to @AeonFlux1603 for this LOS ROM.
    I would like to try it out but would like to know if there are any known bugs/annoyances that might detract me from installing it.
    Also, this tablet is my daughter's tablet. Her being 'minor aged' I would like to have a kid's mode for her where she can only use the apps/games that I approve and prevent her from browsing the web, etc. Is there such a kids mode in LOS 14.1?
    Hope @pndwal or anybody using the rom can clarify these two issues.
    And, by the way @AeonFlux1603, are you planning on releasing security updates for this ROM? Is a LOS 15 in the works? LOS 14.1 should now stop receiving security updates, right?
    Thanks in advance.
    Cheers

    In terms of annoyances, I would have to say that reduced battery life is my #1 pet peeve. I have been trying to track it with GSam Battery Monitor, and it seems to arise because the OS is constantly trying to power the phone radio for an LTE connection that doesn't exist on the TB3-850F tablet. The "phone radio" category of the battery monitor shows a significant power draw, even after I switch to Airplane Mode. This must be a legacy from the origin of this ROM in the TB3-850M hardware.

    I tried using the dialer to enter *#*#4636#*#* and then bring up "Phone Information", which does give an option to switch off "Cellular Radio Power". But that is only temporary, and the slider switch goes back to "On" immediately as soon as you leave the testing app.

    Early in this thread (post #16), @AeonFlux1603 mentioned that he was updating the rom to remove all the LTE vestiges of the TB3-850M that exist, but I'm not sure that he actually got to that point. It's possible that he did, and that I'm accidentally running an obsolete version of this ROM that still contains all the LTE phone radio stuff. But I don't see any reference to that issue in this thread after post #16.

    Could someone please clarify the most current version of this ROM? Mine shows security patch dated May 5, 2017, and LOS version 14.1-20170515-UNOFFICIAL-TB3-850M.

    As for "Kids' Mode", that is no longer a category that you set up through the settings app on the tablet. You can add new users with their own apps & content, or set up a restricted profile, or download an app for this purpose from the Playstore. But the stock "Kids' Mode" from the stock rom is gone.