yashsingh1/xdaforums huggingface dataset:
[Android General] kevink619:
Hi,

Did any of you get this to work? I'm still trying to install the OTA update, but keep getting the "this package is for tb3-850f" devices..." error.
[Android General] MotoJunkie01:
I just compiled the most recent build of stock Android 6.0 released for this device. So, to prevent earlier build users from being required to revert to a full stock setup to accept the OTA, a member can simply perform a wipe in TWRP, and install the TWRP flashable stock ROM, thus putting your device on the most recent build.

Guys I've been gone from this projrct way way longer than I myself expected. I apologize to those of you eagerly awaiting development for this great tablet. I also have captured the OTA zip packages from Lenovo for at least five (possibly six) incremental Android 6.0 updates. If any members request, I will post a separate thread with links for all available OTA zip packages for the TB3-850F stock Android 6.0 OS.
[Android General] Hemphiz:
Thank you mate. Any work is appreciated regarding of timing. It's takes alot of time and effort to work on the things your doing. All good. I shall flash it when I find some spare time myself ??
[Android General] MotoJunkie01:
After much battling with default force encryption and dm-verify on this tablet, I have finally decrypted this device and have compiled an otherwise unmodified Stock 6.0 ROM which is TWRP flashable. I have also updated this ROM to the most current version, which will alleviate any issues with installing OTAs. I will also be updating the stock Recovery Image to the latest version, TB3-850F_S100030_161209_ROW.
[Android General] pndwal:
Great work!

Please would you provide a brief summary of advantages of decrypted device (guess means

disabled

force encryption and dm-verity) for noobs (in sense of uninformed, not new) like me?

Have there been instances of dm-verity warnings being triggered on this device?

Also, is it adventageous if rooted or unrooted? Will it work rooted with Magisk, or need SuperSU?

Many thanks, PW.
[Android General] Hemphiz:
You beast ;) I shall flash this later. Currently using Franco Kernel Updater with per app profiles to try and get some fluidity out of it. As allways, very much appreciate your work bud :svetius:
[Android General] MotoJunkie01:
I'm very close to posting my pre-rooted version of this ROM. However, if you want to root this ROM, simply flash SuperSU v2.82 with TWRP recovery.

Ok, as to force encryption, many devices which run Android 6.0 and later have the /userdata partition encrypted by default. In other words, any music, videos, personal files, etc, that you have stored on your device are encrypted automatically (force encryption). With force encryption disabled, you may still go to SETTINGS>>SECURITY and encrypt your userdata files. The advantage of disabling this feature is that it puts the choice back into the user's hands as to whether or not to encrypt your personal files.

As to dm-verity (device mapping), any alterations to your tablet's partitions or filesystem can render it unable to boot. This feature is marketed as an advantage to the user -- that dm-verity will prevent an unauthorized person from gaining access to your Android OS, and thus, your files. In reality, dm-verity is problematic, and makes it difficult to root a device or otherwise alter its filesystem structure without bootlooping or otherwise soft bricking the tablet. With dm-verity disabled, device owners have much more flexibility when it comes to customizations of the ROM, kernel, recovery, etc.
[Android General] MotoJunkie01:
Haha ....great hearing from you mate. Hope all is well with you.
[Android General] rmleonard:
I'm back too! -- mostly

Hi-ho All! --

a few questions ---

(I'm dusting off the 'lil Brick of a Tablet)

Does anyone have a quick'n'dirty how to on unbricking the Lenovo Tablet?

it is not so bricked that it can't be tricked into booting from an external copy of TWRP.. (at least it did a few months ago)

I am going to try that again in a short while --- (the battery is still charging)

if I can get it into twrp --- I'll try flashing the file I just downloaded (The new Stock Android 6 file)

if that works --- great! --

if not -- What should my next steps be?

When last it worked --- (so say my notes) I was trying to flash the HEMPHIZ

stock rom files using the SPFlashTool --- and I have a sneaky feeling that my inexperience caused an offset on a partition......

so there is a possibility that the internal filesystem is "corrupt" ---

I'll post again in the morning on how things go or went....

Happy Friday (and remember to reset your clocks this weekend - Daylight Savings and all that....) --
[Android General] pndwal:
Many thanks for clear summary!

Couple of related questions:

Re. disabled encryption:

Will device / processes work faster with encryption disabled? And will this affect adoptive storage in any way?

Re. dm-verity:

Is there an option in this ROM to turn dm-verity on or off (as with force encryption)?

Re pre-rooted ROM:

Is there any advantage in supplying ROM pre-rooted? (Some OS customisers (eg OctOS) have dispensed with pre-rooted versions in order to give users greater flexibility.) I ask since I'd like to try Magisk on this device as I like some of its systemless modules, as well as ability to pass Safety net check.

Incidentally, I just noticed Magisk Manager has Advanced Settings to Keep force encryption, and Keep dm-verity. Turns out (from Magisk XDA thread) that these are disabled by Magisk root by default, but can be toggled back on. Read that dm-verity may be needed for OTA updates. Read that leaving Keep force encryption disabled means that if encrypted data is removed (wiped), it won't be encrypted automatically on next boot.

Might try Magisk on tablet soon to see if it does the same job, and report results. Works fine on my Huawei y550 phone with Lineage OS, and seems to be un-encrypted (shows option in Security to Encrypt Phone). Thanks, PW.
[Android General] MotoJunkie01:
My pre-rooted ROM for this device will actually be using Magisk 14.0 Systemless User Interface with full SafetyNet pass. Yes, correct; Magisk Manager does provide advanced options to allow dm-verity and force encryption to remain intact. I've personally never had the slightest use for dm-verity or force encryption. But, that's my personal opinion, and I'm sure there are users who would opt to use these features.

Should Lenovo push any future OTA's for this tablet, I will update the stock ROM in this thread accordingly. My pre-rooted, deodexed ROM, which is presently nearing completion, will include Google's security patches up to August 1, 2017, as well as options to enable the Google Assistant.
[Android General] pndwal:
Sounds great!

Seems your new ROM will be utilising Magisk root as well as it's User Interface (Manager). Just for clarity, will this include your decryption changes, or does Magisk root alone disable dm-verity and force encryption? Many thanks, PW.
[Android General] MotoJunkie01:
By default, the ROM will have neither dm-verity nor force-encryption enabled. Users who want either of those features may configure either or both from Magisk Manager. I see no benefit from either feature, but again this is my personal opinion.

I've chosen Magisk root & systemless user interface over SuperSU for several reasons, including the large number of optional modules available with Magisk, as well as the ability to hide the SU daemon from system and user applications alike.
[Android General] pndwal:
Yes, were on the same page here. But because it turns out that these are

already disabled

by Magisk root by default (but can be toggled back on), and you are including Magisk pre-root anyway, my question was simply: Will this include your decryption changes, or does Magisk root

alone

disable dm-verity and force encryption successfully as per Magisk XDA thread description. (IE. Is Magisk root an out-of-the box solution for this on our tablet?)

Thanks, PW.
[Android General] Hemphiz:
If you Already have TWRP installed then it should be a case of booting to twrp - Format data and wipe system etc. (Not Micro SD, I would use this to load your flashing files) then Flash MotoJunkie's stock rom from this thread via twrp. Works wonderfully. If that fails then SP flash tool is probably your only option (btw I haven't made any stock firmware ;))
[Android General] MotoJunkie01:
When initially flashing Magisk root in TWRP, dm-verity and fstabs are patched, then the patched ramdisk/kernel are flashed to the device. . So yes it does disable dm-verity. Force encryption is not disabled by rooting with Magisk.
[Android General] MotoJunkie01:
I'll be starting a Q & A thread for this device and custom ROM once posted. That way this thread stays on point and does not get off topic.
[Android General] pndwal:
Thanks. Guess this means your decryption changes are needed in addition to Magisk root.

Still a bit confused as Magisk XDA thread says things like "Keep force encryption means that Magisk removes it, so if you delete /data and thus encryption it won't encrypt itself automatically on the next boot" (unless Keep force encryption is enabled), and "It won't magically decrypt your phone. Disabling it just means that when you unencrypt your device it won't be forced to re-encrypt on the next boot." Seems to indicate Force Encryption is disabled natively by rooting with Magisk. Guess I'm missing something somewhere. PW.
[Android General] MotoJunkie01:
Once the ROM is posted, I will dedicate a Q & A thread for all such questions & concerns. This thread must stay on topic to matters directly relating to this ROM. Thanks
[Android General] pndwal:
Wow - comments vanished! But you appear to be right re force encryption requiring more than magisk root on 850f. Seems magisk thread info only applies to some ROMs (including my y550 phone w/ Android N, apparently decrypted thru Magisk root only), so I was under false impression.

However, I thought it was relevant as disabling dm-verity and force-encryption seem to be main changes to otherwise (latest) stock ROM I (and others) already have. Just wanted to understand benefits of changing to yours before going through the pain!

Sorry If I cluttered your topic. Will stop with questions here till you set up your Q & A thread. Thanks for your efforts, PW.
[Android General] MotoJunkie01:
Yes comments vanished because I've been warned by moderators myself to stay on topic. XDA is increasingly strict on that. Please don't take offense or take me wrong on anything. Your questions will be more than welcome on the upcoming Q&A. Thanks for your understanding and continued interest.
[Android General] MotoJunkie01:
[MENTION=7550078]pndwal[/MENTION] I would like to invite you, first & foremost, to the ROM Q&A for this tablet. I'm hopeful that the Q&A will provide answers to relevant questions like yours, and provide input, user experiences, & ideas for future ROM development for the Tab 3 8.

https://xdaforums.com/android/help/qa-lenovo-tab-3-8-tb3-850f-t3700868
[Android General] MotoJunkie01:
I just compiled the new stock build (TB3-850F_S100031_171010_ROW) from Lenovo's recent OTA for the Tab 3 8. This OTA includes minor bug fixes, stability improvements, and Google's security patches up to September 5, 2017. I'm now uploading the ROM and will update the thread & post an updated link when this slow internet at work allows me to finish.
[Android General] MotoJunkie01:
Latest stock build just posted.
[Android General] yiukiang:
Hi Moto, thanks for your contribution.

I have a question: is it possible to update TB3-850F to Nougat 7.0 or 7.1.x something ? If possible, so does the tablet will running slow ??

Mine is Lenovo TB3-850F , running 6.0 and rooted by your method !
[Android General] MotoJunkie01:
Sure, hardware wise, this tablet is capable of running even the most current version of 8.0 Oreo. 7.x.x and 8.x.x custom ROMs would be no problem, if this device had the dedicated development teams that many other devices have. I'm in hopes that a few developers will take interest in the Tab 3 8, and that custom ROM development begins.
[Android General] rmleonard:
Life is..... Well.... Life!

Since my last check-in..... My lovely lil brick of a tablet was sent home.... And the wonderful folk at Lenovo replaced it's motherboard...

So... I now have my tablet back... And am thinking of restarting this exercise again....

With some more experience under my belt.....

First major question.... Has anyone created a version of twrp for this model of tablet? The TB3-850F?

When last we met (when last I downloaded) - the twrp version thought it was the "M" model.....

If not, what drivers/extras are needed to build twrp? If I pull down Lenovo's source will I have all I need?

Since the tablet is working exactly as it is supposed to right now, I am hesitant to start something and then go .... 'Dang!!!!! If only....'

Thoughts on that?

(And I'll start homeworking on the twrp concept)

Rich
[Android General] Hemphiz:
My tablet is TB3-850F. I flashed the twrp in OP and everything went well for me. No issues. Mrmotojunkie has provided everything needed in his thread (there's a couple) check his profile - "find all threads started by." if you are hesitant then just take your time and try again when you feel confident enough
[Android General] MotoJunkie01:
Yes, as [MENTION=6939319]Hemphiz[/MENTION] has correctly noted, the TWRP build I have linked in my various threads works for both the TB3-850M & TB3-850F. I am rebasing TWRP for the 850F to bring it up to date with the upstream sources. However, as [MENTION=6939319]Hemphiz[/MENTION] noted, there are no apparent bugs with the current version being used.

Here is a link for TWRP and other miscellaneous files for TB3-850F. https://drive.google.com/drive/mobile/folders/1l-YN5aXmjDF3O1bHxFHVIxLKuvd847Q9

This thread will allow you to successfully unlock your bootloader, flash TWRP, & root your tablet with the latest SuperSU v2.82-SR5. Follow the instructions exactly and the thread will work for you. https://xdaforums.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786
[Android General] pingupongo:
After doing step 3:

3. Wipe /system, /data, /cache & /Dalvik-ART cache. (Also, select "Wipe", then "Format Data." This step is crucial to ensure disabling of force encryption. Please note that once installed, you may go to "SETTINGS", "SECURITY", and manually encrypt the userdata on your tablet.) Now, Reboot Recovery. This step is necessary to ensure proper mounting of the /data partition;

Tablet doesn't boot in recovery, stays stuck on lenovo bootscreen
[Android General] MotoJunkie01:
In the event that recovery doesn't reboot from TWRP, simply power down and use your hardware keys to reboot TWRP, then proceed with the installation of the ROM.
[Android General] pingupongo:
Thats what I tried, but nothing worked, it looks like bootloop, I tried all possible combinations vol up+power...........I did instal twrp in recovery and then choosen reboot recovery and then it looked like softbricked so I did sp flashtool.

Is the tablet any faster when installing your rom?
[Android General] MotoJunkie01:
Well, it seems that the disabling of forced encryption of the /userdata partition does tend to make the ROM a bit snappier in terms of responsiveness. Then again, that could be my imagination. The custom ROM that I currently have under development for this tablet is geared towards RAM optimization, faster boot time, and better overall performance than the stock ROM.

So, to answer your question, I personally believe that this ROM is a bit faster due to forced encryption being disabled. But again, that's only an opinion based on my personal experience.

By the way, thanks for your input and feedback on your experience which caused your boot loop. I will revise the instructions to omit rebooting recovery after wiping. Since this ROM does not write any data to the /userdata partition, rebooting recovery after wiping shouldn't be necessary anyway.
[Android General] Hemphiz:
I've also noticed this, naturally. Feels alot better
[Android General] Isaac Sailo:
Been using this for about 2 hours, camera and USB OTG are not working. Anyone facing the same issue?
[Android General] MotoJunkie01:
Did you clean flash the ROM, performing a full wipe and formatting data? The camera drivers and support for USB OTG are encompassed within the boot image itself. If you did in fact clean flash the ROM, have you rooted it, or have you in any other way modified it?
[Android General] Isaac Sailo:
I did a full wipe, even internal storage, but unfortunately I might have skipped formatting data!!! Otherwise no modification was made. Ill do a full wipe and format data as well and will post the result here again
[Android General] MotoJunkie01:
Ok. Please do....

Update -- I just booted one of my Tab 3's into TWRP, performed a full wipe and formatted /data. I then installed this ROM and completed setup. I experienced no camera bugs, and the ROM seems to perform normally in general, and OTG support is fully present.

However, if, after doing a full wipe plus formatting /data, if you persist to have the bugs you reported, please let me know. I can compile you a small zip installer which will fully update key firmware partitions.
[Android General] Isaac Sailo:
Thanks a ton mate!!! Since I don't need a working camera on my tablet, I thought I would wait for a new custom rom you're developing.. Until then, let me just stick to this ROM :).. Thanks once again for the help!!!
[Android General] MotoJunkie01:
No problem mate. Now that a new year is about to start, I'm hoping to have all bugs worked out of my custom ROM for this great tablet so that I can get it posted in the next few days. I'm still a bit perplexed as to why your camera is not functioning on my stock ROM. If you followed all instructions carefully and the camera bug persists, it can only be one thing: your partitions need to be updated to TB3-850F_S100031_171010_ROW. Allow me to explain: my ROM flashes only your /system and /boot partitions. The OTA for S100031_171010 actually patches and updates additional firmware partitions such as /tee1, tee2, padA, and /lk (the primary bootloader). The issue you're having with the camera made me think, that my stock ROM could have bugs directly related to the partitions that are still running on an earlier version of firmware. On my Moto G (3rd Gen) ROM threads, I compiled a zip installer that updates the partition index to correspond with the firmware version of the ROM, so that people updating from an earlier version firmware could also update the partition index accordingly. I'm going to do the same thing with the Tab 3 8. I'll include the updater zip in the download link of the ROM. I'm trying to get that finished and posted today. Thanks mate for your user input and feedback.
[Android General] Isaac Sailo:
Thanks a lot mate, I appreciate all your explanations even though I understood half of them haha.. Anyways, if you want me to flash the additional zip, I don't have any problem :good:
[Android General] mcprescribed:
Can help me get this file?

TB3-850M_S100036_171214_ROW
[Android General] MotoJunkie01:
Open this link and translate the page from Russian to English. I believe the firmware version you are looking for is included in this link. There is also an unofficial LineageOS 14.1 build for the TB3-850M.

http://4pda.ru/forum/index.php?showtopic=764969&st=880

Update: After checking the link more carefully, I see that the firmware package is actually Build No. TB3-850M_S100036_171222_ROW, which was released one week after the version you referenced.
[Android General] voland34:
Hi. I'm trying to find a custom rom for this model that improves responsiveness (becoming desperately slow), and found this thread in which a new light and responsive custom rom is mentioned as almost ready, but i'm not sure if it's to be posted here or elsewhere. I cant find it in xda at all. Could anyone get me out of my confusion? thanks a lot to anyone giving some attention to this tablet.
[Android General] pndwal:
I replied to your post on another thread on 13/03/2018 with links to TB3-850M_S100036_171222_ROW and earlier official ROMs, as well as Lineage and Corsair custom ROMs: https://xdaforums.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786/page20, post #193.

Regards, PW.
[Android General] pndwal:
I'm not aware of any genuine custom ROMs for TB3-850F (other than slightly modified stock ROM in this thread.)

However TB3-850Fs close cousin, TB3-850M (with SIM support) now has working ported Lineage OS 14.1 (Android N - not bug free yet). This should work fine if you can get it to install / boot on TB3-850F (ie fool TWRP to install it) as critical hardware / partitioning is essentially the same. (Others report running TB3-850F firmware on TB3-850M and seem only to lack SIM support).

I would try this if I had the time, but I'm happy to wait as [MENTION=7383447]MotoJunkie01[/MENTION] is committed to porting TB3-850F to this ROM properly. See posts #193, #197, #198 at https://xdaforums.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786/page20.

Hope this information helps, PW.
[Android General] voland34:
I'm happy to wait as [MENTION=7383447]MotoJunkie01[/MENTION] is committed to porting TB3-850F to this ROM properly. See posts #193, #197, #198 at https://xdaforums.com/android/general/guide-lenovo-tab3-8-tb3-850f-t3559786/page20.

Good, it seems wise to wait a bit longer for MotoJunkie01's expertise. Thanks, mate
[Android General] MotoJunkie01:
And I am on it guys. I'm sorry for the obvious delay. Motorola Mobility has me out on the road doing tower & RF work at the moment, so it's been much traveling these last few weeks. I'm about to be settled in at home for a couple weeks down time....thank Buddha, Zeus, and the Hunch Back of Notre Dame. I will get work done on this and my other devices. Thanks for you patience and continued interest.
[Android General] pndwal:
Goodoh

[MENTION=5522475]limited_imagination[/MENTION] has been trying to compile a kernel for the 850F See posts #73, 75 & 76 here:

https://xdaforums.com/android/help/lenovo-tab3-8-2016-custom-recovery-t3483454/page8#post76033375

Perhaps you can assist one another. Regards, PW.
[Android General] Diomorgan:
please delete this post, I found I'm in the wrong thresdy.

Very sorry.

:(
[Android General] pndwal:
?? This forum is for TB3-850F. PW.
[Android General] limited_imagination:
Here is the Image.gz file that was produced, and also the Image.gz-dtb file.

I tried to upload the Image.gz-dtb file directly, but the forum software blocked it. So I put it into a Zip archive, and that seems to have been allowed.
[Android General] MotoJunkie01:
Oh wow. Been traveling and just got on here to check out the threads. Lo and behold, I see major progress on our beloved Tab 3. I'll download these files and check out the code. [MENTION=5522475]limited_imagination[/MENTION], much thanks for your hard work. Looks like we are finally getting close to some real development here.
[Android General] pndwal:
Wow, well done with all that. Strange source code was altered that way, and well done finding solution.

Hope [MENTION=7383447]MotoJunkie01[/MENTION] can assist you with getting it booting.

Did you check ported Lineage OS 14.1 for TB3-850M (TB3-850Fs close cousin)? -See post #107 this thread. Guessing it could be useful.

Looking forward to seeing progress with this. Many thanks for your efforts in developing for our device. Regards, PW.
[Android General] Diomorgan:
so sorry I edited and didn't push return .Will do right now. By the way the question is the same, everyone got it's OTA upgrade alert a few weeks ago and maybe applied it? Actually I found that if I use it it doen't reboot, while if I live charging not using it it reboots pretty often. :(