yashsingh1/xdaforums huggingface dataset:
[Android General] pndwal:
Thats what did it. Only format critical partitions in an emergency situation!

As I said, Many accidentally mess up critical partitions using SP flash tool... and have to rebuild emmc partitions normally not affected by custom ROM modding... If you don't have backup, you will need to jump through hoops (using several special softwares) to restore this info. (Even though much of it is duplicated in hard memory (Ie can't be flashed or lost), machine reads it from soft nvram (non volatile, but flashable), and both records must agree - generic or no numbers in nvram won't work properly; correct no.s must be restored).

If things are fortunately working well enough for you, you could leave it I guess, but I don't know what issues you will face in future. People with models with sim(s) need to restore one or two IMEI to restore calling functions, and with generic numbers (which I suspect you now have), BT and wifi issues are reported, as well as Nvram warning messages.

Because of hard memory duplication, it is possible to restore the numbers unique to your device if these partitions (especially nvram) have first been rebuilt properly. (None of these partitions are included in custom ROMs as Devs expect you to leave them as original - there is seldom any functional benefit gained by changing these, or it is simply too hard to alter manufacturer or chipset provider programming here.) By reading back as I suggested, you should find the software needed. (Eg- SN Write Station tool, IMEI and SN Writer, Maui META 3G and SP META).

In future remember - Before any further modding (including, and especially before using SP Flash Tool or the like), once you have TWRP recovery, BACK UP not only boot and system, but also other partitions, especially nvram, if you don't wish to jump through hoops to restore this info!

All the best with it. Hope this helps, PW.
[Android General] pndwal:
Quite. I think some people (actually this includes many of us,) need to learn to educate themselves before modding the hard way. Same goes when using SP flash tool etc. Read read read first and become acquainted with the abundant cautions experienced users have provided on forums like this one, which I think john3voltas now appreciates, especially the oft repeated prompts to Back Up First. I wish him all the best fixing NVRam etc. (It can be done, but will require a little prior reading. :eek: )

I like your revision ideas, but I have a thought: So as not to cause confusion if people want to root and use a different ROM, eg unmodified stock, as well as to save your time, it may pay not to rework this too much, and retain a one-procedure-fits-all solution.

Interestingly, stephenwhite originally said: "I followed the instructions on the web to root my TB3-850M...", so I'm not sure he meant your instructions anyway (and you did help him with unbrick info, emphasizing that this thread is for 850F). :) Regards, PW.
[Android General] MotoJunkie01:
Yeah good point. I've been using the no-verity kernel option in some of my Moto E4 and E5 threads. But, with the Moto E5 at least, having a no-verity kernel is required for root. That's not necessarily the case with the 850F. Force encryption and dm-verity can both be preserved with systemless root. So yeah, I'll likely leave it as is. I think of the few members who have had issues, not reading or not following the instructions closely has been the culprit.
[Android General] RenaKunisaki:
Well I managed to get Magisk installed in place of SuperSU, and it works... except every 5 minutes, it reboots. Was able to restore a backup with SuperSU installed, no problems using that.
[Android General] MotoJunkie01:
Out of curiosity, which version of Magisk did you use? Have you tried my ROM for the 850F which is rooted with Magisk? I haven't heard about any random reboots with this, but I haven't tested it at length either. This ROM is rooted systemless-ly with Magisk v16.7-beta, but because I've been busy with LOS 14.1 for the 850F, I haven't had time yet to update the Magisk version to the current v17.1.

https://xdaforums.com/thinkpad-tabl...k-android-6-0-rom-lenovo-tab-3-t3825165/page3
[Android General] pndwal:
Was that with Magisk 17.1?

As I mentioned regarding whether it is possible to use Magisk on TB3-X70F - 'Should be - unless cobra modified SU is required to root your device - probably isn't but not sure.'

You could try latest standard Super SU to double check if normal unmodified SU options work, but I'm guessing the cobra modification may be required to get stable root on your device.

If you have to restore cobra SU, you could then try flashing Magisk (from TWRP, use 17.1) without uninstalling SU (to see if Magisk can handle SU cleanup while leaving needed cobra mod in boot.img). There's only a slim chance this will work. PW
[Android General] MotoJunkie01:
Great suggestions. In the event that Magisk persists to cause random reboots, perhaps phh-superuser could be used for systemless root on the TB3-X70F.
[Android General] baregonta:
this TWRP works on TB3-850M?
[Android General] MotoJunkie01:
Yes. This TWRP was actually built for the 850M, and later ported to the 850F.
[Android General] issue82:
I bricked 601 LV (equivalent to TB 3 - 850 M?) Which was sold in Japan.

Even if you try the method written in the thread, you will not recover by all means.

Screen does not show at all, it is in a state where TWRP can not be tried.

Can anyone expose the data that read back TB 3 - 850 M with SPFlashtool?

SoC: MT 8735

RAM: 2 GB

Storage: 16 GB

WiFi + LTE Model (There are two SIM slots, but dual SIM is not supported in Japan)
[Android General] MotoJunkie01:
You can try this method for unbricking with the SP Flash Tool. https://xdaforums.com/android/help/lenovo-tab-3-8-tb3-850f-unbrick-root-t3598727
[Android General] issue82:
I tried the method written on that page, but the screen does not show up anyhow ....

(I'm surely trying it over 100 times ...)

Is there any other way ...?
[Android General] MotoJunkie01:
If the screen is not working at all, it sounds as though your device is hard bricked. I wish I could offer guidance, but I am not familiar with the variant,/model you have.
[Android General] issue82:
Currently, when connecting with USB, the PC recognizes it, and if you use SPFlashtool with "M" deleted from Scatter file, it is possible to write. Moreover, it is in a state that the memory test is cleared without any problem.

The specifications are as follows, is this different from TB 3-850M?

Display: 8 inches · 1280 * 800 px

SoC: MT8735 1.3 GHz quad core

RAM: 2 GB

Storage: 16 GB

LTE: Correspondence

WiFi: IEEE 802.11 / b / g / n

SIM card slot: 2 sheets

Early AndroidOS version: 6.0
[Android General] MotoJunkie01:
One thing I've learned about the Lenovo Tab 3, is that there seems to be a few variants of the tablet worldwide. It does appear that you have the 2GB RAM variant of the TB3-850M. Your chipset, the MediaTek mt8735, is listed in the open source code for the 850M stock Android OS. I believe it's safe to assume you have the 850M, which leads me to believe that the SP Flash Tool should recover your device.

Make for 100% certain that your PC/laptop has the proper vCom drivers installed. If you are running Windows 10 (64-bit), you will need to enable Test Signing mode in order to install the unsigned vCom drivers properly. Improperly installed vCom drivers is the most common reason for failure using the SP Flash Tool unbrick method. Google the terms "Test Signing" and "Windows 10" (if you are in fact running Windows 10) for the steps to enable Test Signing mode. Once enabled, try installing the vCom MediaTek drivers again.
[Android General] pndwal:
I found nothing for 601 LV.

Im doubtful it's a TB 3-850M variant as has dual SIMs. (F model appears to have only one blanked off slot).

Is it Lenovo? (Lenovo written on SD cover, or elsewhere?) Can you provide current firmware file name (build), or full model name from box or manual?

How did you brick it? - did you unlock bootloader / Install TWRP successfully, or attempt to do so? Did you flash anything else?

This info will help us to assist. Regards, PW.
[Android General] MotoJunkie01:
There is a Russian variant of the 850M with dual SIM slots, 2GB RAM -- with the mt8735 chipset. Like you I am unable to find a reference to LV 601. If his is in fact the dual SIM variant, I have a factory firmware package for it. The package name is:

TB3-850M_DS_USR_S100004_1606072005_MPMO_SK_BGSECURE.zip

The single SIM variant has nearly the same package name, except instead of "DS_USR," it reads "S_USR" Also, I cannot be certain by package names alone, but the single SIM model may be the 1GB RAM variant. But again, that is speculation.
[Android General] pndwal:
Well found! Perhaps a Russian model sold in Japan. Would but good (for everyones sake) to have a more definitive confirmation of model from him if he has more information than just a dead tablet though. PW.
[Android General] MotoJunkie01:
Yeah definitely. I recall about a year or so ago I thought the Tab 3 8" was simple -- either an 850F or an 850M. I've since learned there are variants of each of those, which break into sub-variants by region. So yeah we need precise info from members as to their model.
[Android General] issue82:
Thank you for the information.

Although I'd like to try it quickly,

>> TB3-850M_DS_USR_S100004_1606072005_MPMO_SK_BGSECURE.zi p

I can not find this package. I do not hit either Russian sites nor Google search.

Where can I get it?
[Android General] pndwal:
That was [MENTION=7383447]MotoJunkie01[/MENTION]'s information.

I said:

Regards, PW
[Android General] MotoJunkie01:
Here is a link for stock firmwares for the TB3-850M that includes around 20 packages for some 850M variants. Hope this helps.

https://easy-firmware.com/index.php?a=downloads&b=folder&id=19515

Because some of these firmwares are leaked and otherwise difficult to find, a fee may be required to download the files. Any package listed as "Exclusive" is fee based. I neither promote nor condone firmware sources that charge money to download files. However, sometimes a specific firmware can be near to impossible to find and fee based sources become the only viable option.
[Android General] MotoJunkie01:
Also, for 850F owners, here's a link for several stock firmware packages.

https://easy-firmware.com/index.php?a=downloads&b=folder&id=19510
[Android General] pndwal:
Thanks, but I can see (or search TB3-850M_S and find) TB3-850M_S_USR_S100004_1606072005_MPMO_SK_BGSECURE.zip, but cannot see TB3-850M_DS_USR_S100004_1606072005_MPMO_SK_BGSECURE.zip (even by searching TB3-850M_DS). PW.
[Android General] MotoJunkie01:
I have several firmwares not listed in the link, including a couple of dual SIM variant packages. It appears that Portugal has a dual SiM variant as well, if I'm correct assuming the "PORTG" region extension name is indicative of Portugal.
[Android General] pndwal:
Right. Guess he'll need to get it from you then. PW
[Android General] MotoJunkie01:
Indeed. I'll upload and post a link soon as possible. Hopefully that'll fix the guy's tablet. Nothing worse than having to stare at a brick.
[Android General] john3voltas:
Interesting. Never seen one of those around here.

Actually, I've never seen a single Sim either.

To be honest, most big retailers seemed to be interested in the 850F only.

If I had found a variant with WiFi and GSM, even for my baby girl, I'd have bought that one instead of the 850F which is WiFi only...
[Android General] MotoJunkie01:
Yeah been the same experience for me as well. Every retailer I've seen that sells the Tab 3 8, it's been the 850F model. Amazon, eBay & Swappa seem to be the only sources for the 850M models. Interestingly enough, although the 850F is marketed as WiFi only, the chipset includes a 4G/LTE baseband radio. It just isn't used on the 850F and the SIM slot has been blocked off by the OEM. With a micro USB SIM dongle, and tweaks to the build.prop, apns-config.xml, eri.xml, telephony.db, etc., It is possible to use GSM data on the 850F. Lenovo made a bizarre decision to market a WiFi only tablet that technically supports cellular data.
[Android General] pndwal:
I think it does make Marketing sense however - there are many like me only in market for WiFi models, to whom they can offer more reasonable prices, and make a better profit from LTE model sales with a little extra cost. (Cellular frequency matching, even LTE bands which have expanded in range since 850M was produced, are confusing in many countries, and can become next to useless when swapping providers unless a large range is implemented at more cost, so I think many are happy to access phone hotspot etc, and pay only one cellular subscription. Also, my understanding is that while modem is included in soc, radio support differs and must be added at some additional cost, as well as coming with an inevitable if small hit on battery performance for M models.) This has been the way they have marketed each series of their TAB devices earlier and later than ours too.

Interestingly, official ref here mentions dual Sim slot, as well as both 1 and 2GB WiFi models (F), but only 2GB LTE model (M): https://support.lenovo.com/us/en/solutions/pd104294 (Incidentally, dropdown at top of this page gives you access to Hardware Maintenance Manual, etc.) PW
[Android General] MotoJunkie01:
Yeah I agree that marketing a WiFi only device makes good business sense. I am only puzzled as to why Lenovo chose a chipset with a reputably decent cellular radio as a platform for a WiFi only device. Surely manufacturing costs could have been less had Lenovo opted for a base WiFi only chipset. Radio support is given to a particular chipset by way of the firmware configuration and at no additional cost to the OEM. The 850F chipset is also the board platform for the Huawei Honor, the LG K4, the Alcatel Pixi 4, etc.
[Android General] pndwal:
Guess it comes down to price chipset can be obtained for.

I'm not familiar with how it works for Mediatek, but my Qualcomm Snapdragon 410 cheap Huawei Ascend Y550 includes "integrated 4G LTE World Mode", and "integrate(s) 4G LTE and 3G cellular connectivity for all major modes and frequency bands across the globe and include(s) support for Dual and Triple SIM."

This is part of the 410 chipset with its "Integrated 4G LTE modem with support for Category 4 speeds..., Support for LTE dual SIM / dual standby (DSDS)," and support for a "Broad selection of RF options, including... Qualcomm Technologies’ RF360 (Front End RF) solution..."

So it includes the LTE modem, but this requires a Front End RF platform Solution to make it work, ie. the cellular radio parts being optional extras. (Your friend's dongle modem solution would necessarily add the RF components to 850F).

My Y550 comes in 3 flavours, L01, L02 and L03, the ONLY difference being the various RF components required to enable different GSM, UMTS and LTE bands for the different regions / networks around the world which comprise another good reason for the OEM to add radio support as per requirements.

Related information from Qualcomm:

So for Qualcomm, radio support is not provided by the chipset (although SOC does include the 'modem'), but by additional front end components (listed above, and I'm guessing given your line of work you are probably more familiar with their function than I am) that allow the additional RF transceiver and the modem to communicate. The ability to exclude both RF front end and RF transceiver parts clearly make it much cheaper, as well as viable, for OEMs to use the same chipsets (although including LTE modem) in WiFi only as well as LTE devices, while also reducing to zero any RF component battery usage (however 'battery-friendly'). - And this is in fact the practice accross the board with OEMs and chipsets, - eg there are many Snapdragon 410 wifi only devices, including Samsung tablets etc.

It's similar with other chipset supported functions too. Eg, my Y550 lacks hardware for NFC although SD410 supports it, clearly because the cost (and possibly the space overhead) for adding necessary extra hardware was considered prohibitive for a budget model phone, but other 410 devices have it. Eg. Most Honor 4x (che1) use a Qualcomm support chip, but the Chinese version uses a different chip vendor altogether. For this reason, XDA custom ROM developer is making two LOS versions for Honor 4x (che1) at this stage. (Incidentally, Y550 users benefit from an unofficial port from his official LOS ROM).

So I'm afraid it seems to me that radio support is NOT given to a particular chipset by way of the firmware configuration and at no additional cost to the OEM, at least for Qualcomm. I imagine all this is much the same for Mediatek devices given that it hasn't made sense for Qualcomm to include radio in SOC, but I'd only be guessing. Hope this is useful somehow. At the least it will keep you on your toes. :) Regards, PW
[Android General] pndwal:
I found MT6735 Processor Technical Brief.

MT6735 does include two modems: 2G/EDGE/WCDMA/TDS/LTE Modem, and C2K Modem, as well as Radio interface (radio control, acquisition and driving circuits) and baseband front-end.

However, as suspected, it requires external additions:

The two Transceiver (RF circuit) chips it controls - MT6169 (For EDGE/TD RF, WCDMA RF, LTE RF) and MT6158 or MT6165 (For C2K RF), ASM (Antenna Switch Module) or FEM (Front End Module), as well as SIM ports.

Other additional support chips for MT6735 include:

MT6605 For NFC (Optionally)

MT6328 For RTC, Audio, Speakers, Microphones, Vibrator, Amplifier & Pulse Charger

MT6625L (RF circuits) For BT RF, GPS RF, FM RF & WiFi RF. PW
[Android General] MotoJunkie01:
That is 100% correct. The 850F, however, doesn't use the MT6735, but rather the MT6735m. Two entirely different platforms. By the way, you do realize that Lenovo has been writing my paycheck for the last nine years right? Lol. You're sort of preaching to the choir. But I admire your willingness and ability to research specs. You would make a skilled dev.

I wish like hell our tablet had the base MT6735. It clocks at a peak 1.5 GHz. The MT6735M has the baked in comms (integrated Cat 4 LTE Modem, hence the "M" suffix), lower energy consumption with the Mali GPU, and clocks at a max 1.0 GHz (although I've seen custom CPU governors take advantage of a 1.3 GHz overclock).

A concept I'm wanting to look into for our tablet is a recent development on the LG K4 (MT6735m). A developer that works with the Inazuma custom kernels has compiled a kernel for the LG K4 with 12 custom scaling governors and a confirmed 1.33 GHz overclock, with no thermal distress to the chipset. The dev I'm speaking of is the same I have working with me on ports for the 850F. I'd love nothing more than to see our clock speeds exceed the rather insufficient 1.0 GHz peak.

In future Lenovo and Motorola Mobility are leaning more towards Qualcomm Snapdragon chipsets, even on low end tablets and smartphones. I believe this to be a great move for the consumer market.
[Android General] pndwal:
It's very confusing. The original Lenovo box sticker for my TB3-850F says: CPU:MT8161P (did Lenovo lie?).

Kernel Auditor, Phone Tester and CPU-Z etc, all report CPU / Vendor as MT8161P, but some report both, listing hardware or SoC as MT6735, but never as MT6735m.

If it is in fact MT6735m, are you saying it also has the RF components on SOC (Ie the transceivers as well as the modems), because as I've been at pains to point out, MT6735 has integrated Cat 4 LTE Modem too.

Anyway, I wasn't intending to preach to the choir, just that everything I've found has indicated Radio support is NOT given to a particular chipset by way of the firmware configuration and at no additional cost to the OEM. (Even with integrated Cat 4 LTE Modem, transceivers and FEM / ASM must be added to MT6735 at some cost, and even if MT6735m includes transceivers also, there would still be FEM / ASM cost to consider).

However, very happy to hear about light on the overclocking front. I'd love to see progress here too. Hope your dev assistant for LOS port has time to help with this too! (And I have to agree with favouring Qualcomm chipsets.) :) PW.
[Android General] MotoJunkie01:
To clarify the point I was making, as to the costs incurred by OEM in enabling radio support, I am referring to our 850F specifically. The mt6735m in the 850F has all integrated comms, including cell radio support. It merely was not used in our variant. However, as I pointed out prior, a micro USB SIM dongle and firmware tweaks have been used and confirmed to enable cellular data on the 850F.

On the mt8161p labeling, there are in fact at least two variants that use the mt8161P. It's not that Lenovo mislabeled device packaging, but appears that they likely used the same packaging for multiple variants. If yours does have the mt8161p, the TWRP build you are using definitely would not work. Nor would my stock ROMs or the SP Flash Tool firmware. All of those were made specifically for the mt6735m. You may rest assured, as sure as the sun will rise tomorrow, that your tablet has the mt6735m. (I did leave some probability of a different SoC. Lol)

But, if you use a root file explorer, open /system/build.prop and check the value for ro.board.plarform, and if that value says mt8161p, then that's what you have. That value is auto generated and will pretty much always be correct.
[Android General] pndwal:
So sorry to labour the point, but since researching Mediatek a little, I am referring to our 850F specifically also, however on digging deeper into the specs for each mt6735 variant, I found that, as is only logical and expected (by me anyway :) ) for a device whose part number only differs in suffix, the architecture of each is virtually identical - they only differ in fixed max clock speeds for CPU and GPU:

MT6735 1.5 GHz / 650 MHz

MT6735A 1.3 GHz / 650 MHz

MT6735M 1.0 GHz / 500 MHz

MT6735P 1.0 GHz / 400 MHz

(Of course, these also affect max resolutions for screen and cameras supported)

I imagine this may have been a labelling exercise to sell chips that haven't passed tests at higher MT6735 speeds, or simply to create lower priced offerings, but I'm guessing here.

ALL share the same Mali T720 GPU (not just M or other suffixed models), as well as 2G/EDGE/WCDMA/TDS/LTE and C2K Modems, Radio interface (radio control, acquisition and driving circuits), and baseband front-end, and ALL OTHER ARCHITECTURE, but NONE have 'all integrated comms, including cell radio support', as RF components including up to two Transceiver chips - MT6169 (For EDGE/TD RF, WCDMA RF, LTE RF) and MT6158 or MT6165 (For C2K RF), ASM (Antenna Switch Module) or FEM (Front End Module), as well as SIM ports, MUST BE ADDED to all MT6735 variants at some cost.

While not understanding the labelling conventions behind A, M, or P suffixes, baked in comms appears to have nothing to do with M suffix as they ALL have integrated Cat 4 LTE Modem and radio control circuitry.

For these reasons I cannot (as yet) agree that 'Radio support is given to a particular chipset by way of the firmware configuration and at no additional cost to the OEM', even with reference to our 850F specifically.

Regarding your friends micro USB SIM dongle and firmware enabling cellular data, the way I see it is that dongle modem solution would necessarily add the needed RF components to 850F, allowing it to work.

I think you are probably spot on regarding mt8161P reporting and label. And you're right regarding my buildprop reporting MT6735M. It does indeed, despite what I said.

Please put me right if I'm incorrect in any of the above. Regards, PW.
[Android General] MotoJunkie01:
It's got a little old to tell the truth. I am employed by the company that manufactures this very device, so I'm not just making up facts out of thin air. I'm sitting in a hotel room after having worked a 15 hour day and you just won't ****ing quit arguing a point I know with 100% certainty to be a fact. But XDA members have been doing a lot of that lately. So yeah it's old man. Quite frankly I'm done arguing this point and I'm tired of XDA. I'm done

Regards.