KN Reddy

ISSUE: Repeated irreparable corruptions of SD storage (Once corruption occurred , if phone is switched off and rebooted it may work for few hours to 2 days, but it will corrupt irreparable , further if we remove micro SD from Lenovo Tablet tb-8704x and put into pc through card reader for repair it will not be recognized in PC (when it is healthy also, will not be recognized by PC), one more issue is that if we format in pc , it will be recognized as corrupt by Tablet) NEW FINDING ON 01.09.2018: later it is found that this (not be recognized by PC) is the problem of card reader USB2.0 (old , 2012) as it’s chip is not compatible with latest SDXC micro USB card (2017), hence irreparability etc cannot be confirmed. Initially I felt, Aparted or SD Fix may solve the issue or at least it will make corrupted card visible to check disk of a pc. As the above apps need root access the following actions taken. TWRP (read only mode selected once entered into TWRP to keep ota update facility) , magisk 16.7, lazyflasher-no-verity-opt-encrypt were installed , Aparted and SD fix were installed, but they could not solve the problem, one more observation is that when I copied one file from internal storage to sd card while in TWRP, SD card corruption occurred upon booting to phone , I was able to browse, read and write in TWRP. During goggling , it was came to my notice that the problem was solved by pre-April ota update, Hence Uninstalled the magisk and system update was (settings>about>system update) it shown build no S000029 (TB-8704X_S000029_170901_ROW) is available hence updated, it was ok but the next update S000031 failed, when tried to install S000031 (from Lenovo Russian) through TWRP.... error 7 strikes. Update: Original S000031 retrived as follows: (i) TWRP is replaced with recovery from full factory fastboot image (from lenovo russian ) (ii) OTA download from System update from phone, it always downloads original S000031 but installation fails, (iii) OTA downloading from system update and choosing remind later instead of install (iv)Flashing of TWRP (v) entering into storage directory (location: root/data/data/com.lenovo.ota/fileslenovoota)and copy it to SD card then to PC Tried to install the above original S000031 with TWRP but error 7 stricken back. Flashed above ( russian) recovery in place of TWRP and tried install from original S000031 it says version required is S000029 The phone always download S0000031 from some secrete website, hence I was unable to download original S000029. However russian S0000029 is downloaded but they do not match with the existing Later It is observed that OTA update patches system.img, boot.img, recovery.img and modem.img Hence, due to presence of twrp, initial ota was not fully completed recovery image was TWRP, The available recovery is related to build S0000026 from factory image (Russian website) but other files were of original (not Russian) and next version I.e. S0000029. In view of this, the phone always download ota of next version i.e. S0000031 compared to system build no i.e. S0000029. So The Tab is stuck up at this build no, now option left (at least with me) is to update with full factory update (zip) which can update all versions, but unfortunately, no such version is available with lenovo / russian website but flash image (fastboot rom S0000026) is available along with necessary tools drivers. Flashing ROM Lenovo Russian website: rom, all ota are downloaded Lenovo Russian website , Back up of system, boot , data was done with twrp and the backup transferred to PC (unfortunately I kept it on desktop instead of other than os drive) Failures: PC : Windows 10 Pro v1709 b16299.125 64bit, Ram 4GB also on Windows 7 Sp1 32 bit The Tablet: Lenovo tb-8704x , made in China, qualcomm Snapdragon, board msm8953, ram 3gb, 16gb rom, 8”, Android 7.1.1 Flashing program QPST 2.7.472.4 Installed VCRdist 2010 x64 by manually The tablet in fastboot mode Bootloader unlocked Firmware files location: C:\QFIL\Images (i.e. names shortened) Program location: windows default installation The driver Qualcomm HS-USB QDLoader 9008 (force installation, by default it was Android ADB ) Result: Sahara failure Other programs tried: (i) Miflash latest (copying files like flash_all.bat hence & partition.xml to at relevant locations from Mi’s fastboot roms). The latest version of Miflash was able to brick the phone, now stock up at Logo. (ii) GNQC-DownLoad-Tool-V1.7.1.0 (iii) QcomDLoader_1.0.2, QcomDLoader_1.0.3, QcomDLoader_1.0.6 (iv) Qualfast_v1.0.2 (it was able to flash only recovery and boot) Result: failures Only. Success: PC OS: Windows 10 Pro v1709 b16299.125 64bit, Ram 4GB The Tablet: Lenovo tb-8704x , made in China, qualcomm Snapdragon, board msm8953, ram 3gb, 16gb rom, 8”, Android 7.1.1 Compatible program QPST.2.7.460 (the version’s success with 1st attempt itself) While installation it removed 2.7.472.4 remaining files Installed VCRdist 2010 x86 by program itself The tablet in deep flash mode (not in fastboot mode)(further it is in bricked condition with locked at Lenovo Logo but TWRP , fastboot modes working, Bootloader unlocked tablet was kept off from TWRP). Deep flash cable was already available with for mi make phones. Firmware files location: C:\QFIL\Images (i.e. names shortened) Program location: windows default installation The driver Qualcomm HS-USB QDLoader 9008 auto installed when Lenovo Tablet tb-8704x is kept in deep flash mode (it will not respond to adb or fastboot command ) All OTA zip files downloaded from russian lenovo website to PC are copied to SD Card (Micro SD card formatted by smdk_fat322 i.e. smart disk fat 32 on PC was able to mount on Tablet successfully). Updated one by one( boot phone once after one update) through stock recovery. Update: (i) driver HS-USB QDLoader 9008 Version 2.1.12 (19.03.2014) to be installed / chosen and PC to be restarted. (a) adb.exe reboot edl (not working on TB-8704x) (b) fastboot -i 0x2b4c oem reboot-edl (not working on TB-8704x as such commands are not included by Lenovo ) (c) fastboot oem reboot-edl [failed (remote: unkown command Rechecked : Deep flash cable method (may be = EDL) is must . (ii) Windows is in Test Mode for uninstalling / installing unsigned drivers (iii) QPST.2.7.472.4 (2018 latest) also flashing very well (iv) QcomDLoader_1.0.6 also flashing very well , it is slower than QPST or Miflash, the default names appear in the program window to be replaced with actual names of file at 3 places. (v) Even Miflash ver 2016, 2017 , 2018 (latest ) also flashing very well (but they may be risky) further all auxiliary files like flash_all.bat, flash_all.sh ... which are at out side folder of images folder of some fastboot MIUI image are to be copied to outside folder of images of tb-8704x (any copying / deleting of files inside images should not be done) (vi) Qualfast_v1.0.2 is not working Update2 Deep flash cable is not must, switch off tablet, press and hold “vol up” and connect usb it will enter into edl mode