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[GUIDE] Restore G Tablet after a Failed Recovery Mode "update.zip"


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#1 djab

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Posted 13 July 2011 - 08:58 PM

GUIDE - Restore G Tablet after a Failed Recovery Mode "update.zip"

======================================================================
Table of Contents
======================================================================

GUIDE CHAPTERS

A ) CAUTION!!!!!
B ) GUIDE INFORMATION
C ) THANK YOUS!!!
D ) VALUABLE INFORMATION
E ) ALTERNATIVE SOLUTIONS
F ) BACKGROUND
G ) PROBLEM DESCRIPTION
H ) FAILED ATTEMPTS
I ) KEY TERMS & NOTES
J ) SYSTEM AND UTILITIES USED
K ) SOLUTION STEPS
L ) FINAL THOUGHTS

APPENDIX CHAPTERS

M ) APX MODE AND NVFLASH TIPS
N ) WINDOWS USER NOTES

======================================================================
A ) CAUTION!!!!!
======================================================================

The steps presented in this guide are aggressive. You do not need a microSD card in the G Tablet, so it should be removed before beginning to prevent an unintended impact. Also, one of the steps involves partitioning the internal SDcard memory, all the data stored there will be wiped.

======================================================================
B ) GUIDE INFORMATION
======================================================================

This guide is divided into chapters which were outlined above in the Table of Contents. The chapters are broken down into one or more sections and/or steps. I believe reading through the entire guide at least once to develop understanding is the first step to potentially restoring your G Tablet. However, if you are already familiar with the various tools and methods used below you are welcome to jump right into the "K ) SOLUTION STEPS" chapter.

My objective in this guide was to provide all the steps I used to successfully restore the G Tablet. There are probably unnecessary steps in these instructions. You are more than welcome to skip any steps you deem unnecessary.

As you read through the guide you will notice that three main "tools" are used in various steps. The tools used are nvflash, ADB, and Recovery (both Stock and ClockWorkMod ). nvflash is the only tool you need to get started assuming you can put the G Tablet into APX mode (instructions on entering APX mode are in this guide).

Note that there are alternatives to accomplish the tasks where I used ADB. If you know or find another way to accomplish the "ADB" tasks, go ahead and substitute with the other method. Again, my objective was to detail the exact steps I used and ADB was one of my tools.

Although I cannot assume this guide will work for anyone else, if you happen to be in the same position as I was, then hopefully it will work for you too. Even if you are not successful, you might take away a piece that eventually leads to your solution. That is what happened for me by carefully following the recovery steps others so graciously posted. Of course there is a risk that matters could become worse.

If for some reason my links fail or are removed, you should be able to find the needed files and information with some forum and/or google searching.

======================================================================
C ) THANK YOUS!!!
======================================================================

Big Thank Yous to all the hard working developers who made the apks, scripts, and roms I used to restore my tablet. And just as important, the documentation they make readily available.
Special thanks and acknowledgement; roebeet, bekit, goodintentions, rr5658, Mp4, and Titanium Track's.
And thank you to the people who moderate and make sites like slatedroid.com and xda-developers.com possible. They are both invaluable sites to me.

======================================================================
D ) VALUABLE INFORMATION
======================================================================

======================================================================
E ) ALTERNATIVE SOLUTIONS
======================================================================

The solution that worked for me is not the only working solution available. In fact, depending on your situation, one of the alternatives may be a better solution for you. Thank you to all who have posted solutions that worked! I read a lot of posts and all of the information contributed to what finally worked for me. The purpose of this post is just to add another series of steps and give decent detail, hoping that they help someone else. Here are a few other solutions you should review to see if they would be better for your situation:

======================================================================
F ) BACKGROUND
======================================================================

A day after receiving the Viewsonic G Tablet from Woot, I was ready to get a custom ROM flashed on it. Even before placing the order I had a ROM chosen, CyanogenMod's 7.0.3-Harmony with Google Apps version 20110613.

I need to state something upfront. I like CyanogenMod's ROMs and greatly appreciate all they do in the android community. It was my favorite ROM on my Droid Incredible (no longer my primary device) and the ROM is working well on a friend's Viewsonic G Tablet (that tablet was ordered from a different retailer and a month or so before mine). I do NOT / will NOT blame any developer/themer/modder when something I chose to flash messes up the device. My choice, my risk, my consequence.

I followed CyanogenMod's “Viewsonic G Tablet: Full Update Guide” exactly:
  • installed ClockworkMod_Gtab_v08.zip (renamed to update.zip) with Stock Recovery
  • installed CyanogenMod and Google Apps zip files with ClockworkMod Recovery
I wasn't going to use ROM Manager for the install even though it was an option presented. I have done a lot of ROM flashing on my Droid Incredible and now Thunderbolt and have learned I get the best results when flashing from Recovery.

One step I did not do was backup. I should have used ClockworkMod and/or nvflash (didn't know about nvflash yet) to do a backup, but figured since I had made no changes out of the box, why bother? Had I done a backup, I might have saved hours upon hours of trouble shooting. Live, fail, and learn.

Note: This guide does not cover nvflash backup, but I included a couple of links in the "M ) APX MODE AND NVFLASH TIPS" chapter.

Once the installs finished on ClockworkMod, I wiped cache, factory reset/user data delete, and then selected system reboot. I soon realized I had a problem.

======================================================================
G ) PROBLEM DESCRIPTION
======================================================================

No matter what I did, I could not get the tablet to boot. No combination of pressing and holding keys would boot the tablet into any mode. All I could get was blank screen. (Note: Early on in this process I knew nothing about APX Mode.)

Unfortunately, I did not check the original stock bootloader version. I assume it was 1.1, but I really don't know. I read a few forum disaster postings that seemed to be from flashing Woot purchased G Tablets.

I think I had APX Mode available the whole time. I was well into the process of trying to restore the tablet before I started to understand APX Mode. At one point I did try a “shorting the circuit” solution, so it is possible that I had lost APX Mode too and got it back after the “shorting”. Although I am pretty confident I had APX Mode available the whole time.

======================================================================
H ) FAILED ATTEMPTS
======================================================================

I spent many hours trying different solutions posted on various forums. Although no one solution fixed my tablet, I believe working through them resulted in the steps that led to a working solution for me.

Brief descriptions of solutions tried (I even combined some in different patterns to find what would work):
  • nvflashing back and forth between 1.1 and 1.2 based ROMs (stock and custom)
  • nvflashing froyo, gingerbread, and honeycomb ROMs (some stock, mostly custom)
  • “shorting” the internal connections
  • fully draining the battery
As it turned out the more aggressive attempts by “shorting” internal connections and draining the battery were probably not really needed in my case. These appear to be techniques for getting APX Mode back. I don't think I ever lost APX Mode.

I spent at least 30 hours before finding the right combination of steps that restored the tablet. It all came together the morning of July 4, 2011 (Happy Birthday U.S.A.)

======================================================================
I ) TERMS & DEFINITIONS
======================================================================

  • APX Mode - Hold down “Volume minus” key and press “Power” key for a couple seconds.
  • APX Mode check - APX Mode and the USB connection with the computer can be checked by typing lsusb in a Linux terminal window. The “Bus Device” will include a line containing “ID 0955:7820 NVidia Corp.” if the tablet is in APX Mode.
  • Recovery Boot - Hold down “Volume plus” key and then press and hold “Power” key until Recovery is booted (does not matter whether Stock or ClockworkMod recovery is installed).
  • Volume Keys - I was messed up by the volume key plus and minus placement at first (I am new to tablets). When holding the tablet as portrait with the navigation buttons (Home, Menu, Back, and Search) at the bottom, the Volume minus key is closest to the top and the Volume plus key is farthest from the top.
  • SDCARD - I used the tablet's internal SDCARD for the entire process. No microSD card was in the tablet's slot.
  • Hash - I strongly recommend checking a downloaded file's hash when the checksum is provided. If not provided, then at least check to see if the downloaded file is the same size as the one posted.
  • Terminal Commands - Terminal commands (including adb shell commands) are bold-green for clarity. Example: ./nvflash_complete.sh
  • File Paths/Names - File paths and names are bold-blue for clarity when they are not part of a command. When file paths/names are part of a command they will be bold-green.
  • Linux User - It is assumed work is performed as a normal user with sudo privileges and from the user's /home/user/ file location.
  • Shell Scripts - Note the . (dot) and / (forward slash) in front of the script commands (the ones that have the extension .sh). The dots are sometimes hard to see.
  • USB Debugging - Whenever you are successful in reaching a full boot into the tablet's OS, one of your first tasks is to go into Settings-|Applications-|Development and make sure USB debugging is on.
  • nvflash - instructions below cover downloading and what to do with the program and shell scripts.
  • adb – Android Debug Bridge (adb) will be used below. It is assumed adb is already set up on your computer. For reference - I used the instructions at this link to setup the Android SDK without eclipse on my Linux Mint Debian computer - Linux Mint Forums • View topic - How To: Android SDK/ADB setup for lmde *Updated 1/29/11*
  • Methods - If you haven't already, read up and learn about APX Mode and Recovery Mode. They are different and the steps below use one or the other for flashing/installing.
  • READ - Read this entire post and read the referenced, linked information before you start executing the steps.

======================================================================
J ) SYSTEM AND UTILITIES USED
======================================================================

Computer -
  • OS – Linux Mint Debian (32 bit)
  • Desktop Environment - Gnome
  • Gedit – used for editing shell scripts
  • Archive Manager – used for extracting
  • Terminator – terminal program that allows multiple running sessions within the same window pane.
  • Nautilus 2.30.1 – file browser, used for moving files around, selecting scripts for editing, checking file permissions, and setting up directories
  • nvflash
  • adb
Viewsonic G Tablet -
  • Purchased from Woot on June 28, 2011
  • Model - UPC300-2.2

Note to windows users - The steps in this guide are not exclusive to any particular OS. The appendix at the very bottom lists the different downloads needed and other differences when using a windows computer.

(continued in next post)

Edited by djab, 27 July 2011 - 09:44 PM.

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#2 djab

djab

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Posted 13 July 2011 - 08:59 PM

GUIDE - Restore G Tablet after a Failed Recovery Mode "update.zip"
(continued from previous post)

======================================================================
K ) SOLUTION STEPS
======================================================================
----------------------------------------------------------------------
01 ) FILES NEEDED & LINKS
----------------------------------------------------------------------

These are not direct download links, but rather links to the pages where the download links can be found. The information on these pages is worth understanding as well. List format meaning key - type of files - file description/reference - file name/link.
If you need the Android Debug Bridge (adb), then install Google's Android SDK. ADB is a tool within the Android SDK package.
  • Android SDK download page - Download the Android SDK
  • Android SDK Install information - Installing the SDK
  • Additional help with installing the SDK and adb can be found by googling something like "how to install android sdk" or "how to install adb".
----------------------------------------------------------------------
02 ) SET UP
----------------------------------------------------------------------
This is an important part of the process. Setting up the folder structure and placing the tools used within the structure made execution easier for me. Here are a couple of reasons why:
  • The nvflash shell script files expect the program and bin file to be in the same folder. The same would be true if using windows and the nvflash batch file.
  • Some of the files used in this process have the same or very similar names. Organizing before execution helped me keep track of where I was in the process and what needed to be done next.
a ) Folders
Create the following folders and sub-folders in your Linux working directory (assumed to be /home/user/):
  • /gtab/nvflash/format/
  • /gtab/nvflash/vgdum/
  • /gtab/nvflash/off12fw/
  • /gtab/adb/off12fw/
  • /gtab/adb/ml110/recovery/
  • /gtab/adb/ml111/recovery/
b ) nvflash - program, bin, and shell scripts
  • Extract nvflash_linux_2010110500.tar.gz
  • Create 2 new versions of the nvflash_gtablet.sh shell script.
  • Open nvflash_gtablet.sh for editing.
  • File Save As nvflash_complete.sh (do NOT close after save as)
  • Change the following line:
    From -
    sudo ./nvflash --bct gtablet.bct --setbct --bl bootloader.bin --configfile gtablet.cfg --create --go

    To -
    sudo ./nvflash --bl bootloader.bin --download 9  part9.img --go

    To alternative - I learned from burbley's post.
    sudo ./nvflash -–bl bootloader.bin --sync --go

    Note - The dashes in the script lines above are two dashes with no space between. If you try to copy & paste, be sure to double check the syntax.
  • File Save As nvflash_boot.sh (ok to close now)
  • Place copies of nvflash, bootloader.bin,nvflash_boot.sh, and/or nvflash_complete.sh in the following file directories as indicated (made execution easier for me):
  • Folder = /gtab/nvflash/format/ - Files = nvflash, bootloader.bin, nvflash_boot.sh,nvflash_complete.sh
  • Folder = /gtab/nvflash/vgdum/ - Files = nvflash, bootloader.bin, nvflash_boot.sh, nvflash_complete.sh
  • Folder = /gtab/nvflash/off12fw/ - Files = nvflash, bootloader.bin, nvflash_boot.sh, nvflash_complete.sh
  • Folder = /gtab/adb/ml110/ - Files = nvflash, bootloader.bin, nvflash_boot.sh
  • Folder = /gtab/adb/ml111/ - Files = nvflash, bootloader.bin, nvflash_boot.sh
[/list]c ) File movement and extraction
  • gtab.nvflash.1.2.branch.20110508 with cwmv3028.zip
    • Move to /gtab/nvflash/vgdum/, extract contents.
    • Move contents of extracted folder /gtab.nvflash.1.2.branch.20110508 with cwm up to /gtab/nvflash/vgdum/.
    • Delete the /gtab.nvflash.1.2.branch.20110508 with cwm/, folder (it should be empty now).
  • FORMAT.zip
    • Move to /gtab/nvflash/format/, extract contents.
    • Move contents of extracted folder /FORMAT/ up to /gtab/nvflash/format/.
    • Delete the /FORMAT/ folder (empty).
  • gtab.nvflash.1.2.branch.20110617.zip
    • Move to /gtab/nvflash/off12fw/, extract contents.
    • Move contents of extracted folder /nvflash1.2/ up to /gtab/nvflash/off12fw/.
    • Delete the /nvflash1.2/ folder (empty).
  • gtab.Mountain.Laurel.1.1.0.rar
    • Move to /gtab/adb/ml110/, extract contents.
    • You should now have - /gtab/adb/ml110/update.zip and /gtab/adb/ml110/recovery/command.
  • gtab.Mountain.Laurel.1.1.1.suppl.rar
    • Move to /gtab/adb/ml111/, extract contents.
    • You should now have - /gtab/adb/ml111/update.zip and /gtab/adb/ml111/recovery/command
  • z4root.1.3.0.apk
    • Move to /gtab/adb/off12fw/.
  • TitaniumBackup_latest.apk
    • Move to /gtab/adb/ml111/.
----------------------------------------------------------------------
03 ) CHECKLIST
----------------------------------------------------------------------
  • Double check the folders and files established in “SETUP”.
  • Use the terminal for running nvflash and adb (I had two terminal windows open at the same time; one for nvflash commands and the other for adb commands).
  • Check the permissions on all nvflash (5 copies in 5 different folders), nvflash_boot.sh (5 copies in 5 different folders), and nvflash_complete.sh (3 copies in 3 different folders) files using your file browser:
  • right-click, select "Properties",
  • left-click "Permissions" tab,
  • make sure the check box for "Allow executing file as a program" is checked,
  • left-click "Close".
----------------------------------------------------------------------
04 ) EXECUTION
----------------------------------------------------------------------
a ) Terminal command line
  • All commands are run in a terminal session window. Open two terminal session windows, keep both visible if possible.
  • “nvflash terminal” - In one terminal Navigate to /gtab/nvflash/.
    From here on I will refer to this as the “nvflash terminal”.
  • “adb terminal” - In the other terminal Navigate to /gtab/adb/.
    From here on I will refer to this as the “adb terminal”.
b ) Flash FORMAT.zip utility
  • “nvflash terminal” - Navigate to /gtab/nvflash/format/, put tablet in APX mode.
  • “nvflash terminal” - Type ./nvflash_complete.sh; Press enter (do NOT hold any volume keys)
  • Once the script completes, the tablet should display the “Magic Value Mismatch” error, which is ok.
  • Press the power button to turn the tablet off.
c ) Flash gtab.nvflash.1.2.branch.20110508 with cwmv3028 rom
  • “nvflash terminal” - Navigate to /gtab/nvflash/vgdum/, put tablet in APX mode.
  • “nvflash terminal” - Type ./nvflash_complete.sh; Press enter (do NOT hold any volume keys)
  • Note - The tablet should boot all the way into the gtab.nvflash.1.2.branch.20110508 with cwmv3028 rom. If for some reason is does not, make sure the tablet is off and skip down to step "e )" below.
d ) Tasks in gtab.nvflash.1.2.branch.20110508 with cwmv3028 rom
  • Nothing really, just go to the home screen, press the power button, and select power off.
e ) Boot gtab.nvflash.1.2.branch.20110508 with cwmv3028 rom
  • “nvflash terminal” - Navigate to /gtab/nvflash/vgdum/, put tablet in APX mode.
  • “nvflash terminal” - Type ./nvflash_boot.sh, BEFORE pressing enter, hold down the Volume plus key on the tablet. Keep holding until the tablet has booted into Stock Recovery, press enter
  • If all went well you should now be in ClockworkMod recovery.
  • ClockworkMod tasks -
    • wipe cache partition,
    • wipe data/factory reset,
    • partition SDCARD 2048 and 0,
    • reboot system
  • Comment - You are now back where you started, a blank screen. No worries, not done yet.
f ) Flash FORMAT utility (yes we are going to do this again)
  • “nvflash terminal” - Navigate to /gtab/nvflash/format/, put tablet in APX mode.
  • “nvflash terminal” - Type ./nvflash_complete.sh, press enter (do NOT hold any Volume keys)
  • Once the script completes, the tablet will display the “Magic Value Mismatch” error again.
    Press the power button to turn the tablet off.
g ) Flash gtab.nvflash.1.2.branch.20110617
  • “nvflash terminal” - Navigate to /gtab/nvflash/off12fw/, put tablet in APX mode
  • “nvflash terminal” - Type ./nvflash_complete.sh, press enter (do NOT hold any Volume keys)
  • The tablet should now boot all the way into the stock gtab.nvflash.1.2.branch.20110617 rom.
  • Before powering down, there are a few tasks to do in the gtab.nvflash.1.2.branch.20110617 rom:
    • tablet - Turn on “USB Debugging” in settings, applications
    • computer - Navigate to “adb terminal” to /gtab/adb/off12fw/; Type adb install z4root.1.3.0.apk, press enter
    • tablet - launch the z4root app and select Temporary. When done, return to home screen.
    • tablet - launch esFileExplorer and navigate to SDCARD/
    • computer - go to your “adb terminal”, you should still be in the /gtab/adb/off12fw/ directory. Type adb shell and press enter;
    • Note -To verify you are in the adb shell, Type ls. If the result is a tablet directory and file listing, then you are in.
    • computer -Type su and press enter.
    • Look at the tablet, “Superuser” should be prompting you for permission. Make sure the “always allow” box is checked and press "ok". The adb shell session should now display the # (pound sign) prompt instead of the $ (dollar sign) prompt.
    • computer -Within the adb shell as superuser complete the following:
      • cd sdcard and press enter
      • mkdir recovery and press enter
      • exit and press enter (backs out of superuser)
      • exit and press enter (exits adb shell).
    • computer -Now do the following in the “adb terminal”
      • Navigate to /gtab/adb/m110/
      • Type adb push update.zip /sdcard/update.zip and press enter (wait until it finishes, big file – takes time)
      • Type cd recovery and press enter
      • Type adb push command /sdcard/recovery/command and press enter
    • tablet - using esFileExplorer, confirm that the "pushed" files are in the right location; /sdcard/update.zip and /sdcard/recovery/command
    • computer - execute the following commands:
      • Type adb shell and press enter
      • Type su and press enter
      • Type reboot recovery, HOLD the Volume plus key on the tablet and press enter
  • You are now back to the blank screen. Still ok, more to do. If by chance you actually landed on the Stock Recovery screen, then skip down to step "h ) 3." below.
h ) Boot gtab.nvflash.1.2.branch.20110617 Stock Recovery
  • “nvflash terminal” - Navigate to /gtab/nvflash/off12fw/, put tablet in APX mode
  • “nvflash terminal” - Type ./nvflash_boot.sh (note - we are using the “boot” shell script this time), BEFORE pressing enter, hold down the Volume plus key on the tablet. Keep holding until the tablet has booted into Stock Recovery. Press enter
  • You should now be in Stock Recovery and it should have immediately started applying the update.zip file from gtab.Mountain.Laurel.1.1.0.rar you pushed earlier with adb. Once the update completes, you will still be in Stock Recovery.
  • Do the following in Stock Recovery:
    • wipe cache partition
    • wipe data/factory reset
    • select "reboot system" (do NOT hold any volume keys).
  • Comment - I think this boot was the first time I saw the three birds since messing the tablet up! However, I still had more to do before testing a power button boot.
  • The tablet should now boot into roebeet's Mountain Laurel 1.1.0 rom (good signs to note - “3 birds”, “Mountain Laurel” splash, “Honeycomb” animation. Be patient, booting a new rom can take some time.)
i ) Tasks to complete in booted Mountain Laurel 1.1.0 rom
  • tablet - make sure USB Debugging is on.
  • tablet - launch esFileExplorer and navigate to the internal SDCARD.
  • Complete the following:
    • delete the existing update.zip file;
    • Navigate into the /SDCARD/recovery folder;
    • delete the existing command file
  • computer - select your “adb terminal” and do the following:
    • Navigate to /gtab/adb/m111/;
    • Type adb push update.zip /sdcard/update.zip and press enter (wait until it finishes, big file – takes time);
    • Type cd recovery and press enter;
    • Type adb push command /sdcard/recovery/command and press enter
  • tablet - using esFileExplorer, confirm that the "pushed" files are in the right location; /sdcard/update.zip and /sdcard/recovery/command
  • computer - execute the following commands:
    • Type adb shell and press enter
    • Note - Since this rom already has root, you should be superuser upon entering the shell (should see the # prompt). If not ($ prompt instead), then type su and press enter. Confirm with tablet's superuser permissions request if prompted.
  • computer - Type reboot recovery, HOLD the Volume plus key on the tablet until the tablet boots into recovery, press enter.
  • Comment -If successful, you are now back to Stock Recovery and this is the first time you haven't been stuck in APX mode. However, we are still not done.
  • You should now be in Stock Recovery and it should have immediately started applying the update.zip file from gtab.Mountain.Laurel.1.1.1.suppl.rar you pushed earlier with adb. Once the update completes, you will still be in Stock Recovery.
  • Do the following in Stock Recovery:
    • wipe cache partition
    • wipe data/factory reset
    • select "reboot system" (do NOT hold any volume keys)
  • Tablet should now boot into the Mountain Laurel 1.1.1 rom. Again, no halt in APX mode. Still not done, we need to do some cleanup.
j ) Tasks to complete in booted Mountain Laurel 1.1.1 rom
  • tablet - make sure USB Debugging is on.
  • tablet - launch esFileExplorer and navigate to the internal SDCARD.
  • Complete the following:
    • delete the existing update.zip file;
    • Navigate into the /SDCARD/recovery folder;
    • delete the existing command file
  • Note - Some apps were not showing up in Google's Android Market, so I followed roebeet's "Market fix" instructions that are documented in the Mountain Laurel rom posting.
  • Since we already have adb up and running, let's use it to push the TitaniumBackup_latest.apk.
    • computer - “adb terminal” - Navigate to /gtab/adb/ml111/; Type adb push TitaniumBackup_latest.apk /sdcard/Download/TitaniumBackup_latest.apk and press enter
    • Note - I just "pushed" the apk to the tablet's /sdcard/Download/ folder instead of installing it like we did with the z4root.1.3.0.apk previously. I then used esFileExplorer on the tablet to navigate to the folder, then pressed the TitaniumBackup_latest.apk, and selected install.
    • Follow roebeet's Mountain Laurel instructions for the rest of the fix.
----------------------------------------------------------------------
05 ) TESTING
----------------------------------------------------------------------
  • Power off your tablet.
  • Wait a couple minutes to be sure it is off.
  • Press the power button to turn the tablet on (do NOT hold any Volume keys unless you intend on entering APX Mode or Recovery)
  • Tablet should boot into Mountain Laurel 1.1.1 rom
----------------------------------------------------------------------
06 ) DONE!
----------------------------------------------------------------------

======================================================================
L ) FINAL THOUGHTS
======================================================================

I have only applied this solution once to one tablet. I do not plan on recreating the APX Mode problem to run through this again. Why? Our household only has one G Tablet and it has since been given to my wife as a birthday present.

I do not know exactly why this sequence worked for me when nothing else I tried did. I leave it to the wonderful expert developers who created the tools and documentation I used to figure out the whys (if they so desire).

Why Mountain Laurel? Because it was coming from a respected and well published developer and it was based on 1.2 branch. It worked in my restore attempt, so it needed to be in my steps. You can try a different custom rom if you want, but I would recommend against anything Honeycomb (only until your tablet is restored). After restoration, I followed roebeet's Brilliant Corners rom instructions and successfully flashed Brilliant Corners over Mountain Laurel with no issues. I have also successfully followed roebeet's instructions in the Brilliant Corners rom post to switch back and forth between Stock and ClockWorkMod Recovery with no issues.

I truly hope these instructions help someone else restore their Viewsonic G Tablet. Good Luck!

djab67

(appendix in next post)

Edited by djab, 28 July 2011 - 08:25 AM.

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#3 djab

djab

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Posted 13 July 2011 - 08:59 PM

GUIDE - Restore G Tablet after a Failed Recovery Mode "update.zip"
(continued from previous post)

APPENDIX

======================================================================
M ) APX MODE AND NVFLASH TIPS
======================================================================

Understanding APX Mode and how to use NVFLASH when in APX Mode was the most confusing piece for me to learn. It seems that others also struggle with the relationship between the two and how they are used.

APX Mode is a low level “on” state for devices with the tegra chips. I equate it to the “Bootloader” level on my HTC android phones. That comparison may not be entirely accurate because it seems APX Mode is at an even lower level than a Bootloader. The important point is both exist before any Recovery Mode (for example; Stock Recovery or ClockWorkmod Recovery).

NVFLASH is a program used to “flash” partitions (one or more) from a computer to the G Tablet when the gtablet is in APX Mode. NVFLASH can be used to flash just one or multiple partition images. NVFLASH should be run from a terminal session (command prompt in windows) since it needs various expressions and/or options defined when it is executed. The NVFLASH program can also be called from a script file (filename.sh) in Linux or a batch file (filename.bat) in windows. In the steps presented above, NVFLASH is run through script files.

----------------------------------------------------------------------
01 ) APX MODE TIPS
----------------------------------------------------------------------

Understanding APX Mode and how to use NVFLASH when in APX Mode was the most confusing piece for me to learn. It seems that others also struggle with the relationship between the two and how they are used.

To place the G Tablet in APX Mode I held down volume minus key and then pressed the power button for a second or two before releasing both. I did this with the G Tablet connected to my laptop via usb (mini usb port on the tablet and standard usb port on the laptop).

Validating a connection in APX Mode involved opening a terminal session (on the laptop) and typing the command lsusb. If the resulting output included a line containing “ID 0955:7820 NVidia Corp.”, then I knew I was connected to APX Mode with the laptop.

The G Tablet never gave me an indication that I was in APX Mode other than maybe a brief flash of light. Mostly I was staring at a blank screen and did not see any splash images. That is why I would validate the connection with the lsusb command.

Sometimes it would take a couple of attempts for me to get into APX Mode and establish a connection.. To set up a second attempt I would press the power button and then hold the volume minus and press power again. After each attempt I would check connection with lsusb.

IMPORTANT - An APX Mode connection is all that is needed to start the G Tablet restore steps. Recovery Mode (Stock or ClockWorkmod) and ADB are not needed to start. If the early APX Mode steps are successful then you will have access to those tools later on. When I messed up my G Tablet, the only thing I had to work with in the beginning was APX Mode and early on I didn't even know I had that. From my perspective all I had was a blank screen.

If APX Mode and connection to your PC cannot be obtained the first thing to do is check your drivers assuming your OS is windows. I never had a driver issue running Linux Mint Debian. You can find windows driver information at this site -Viewsonic GTablet For Dummies - nvflash.

If you think the drivers are ok and you still can't put the G Tablet in APX Mode, then you next step would be to research some “hard reset” options like “battery draining” and/or “unplugging the battery and shorting connections”. I am not addressing these methods in this post, but you can find techniques and information on this site and others with a little searching.

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02 ) NVFLASH TIPS
----------------------------------------------------------------------

NVFLASH is used when a G Tablet is in APX Mode. Do not use just any ROM download when using NVFLASH! It is important to make sure the ROM being used was set up for NVFLASH. When you extract a NVFLASH ROM download you will see the multiple files with the .img extension.

A “regular” ROM image usually just contains an “update.zip” file along with a “recovery” folder. Within the “recovery” folder there is usually a “command” file. A “regular” ROM image is applied using Recovery Mode, NOT nvflash. Again, make sure you are matching the downloads with the right application tools.

If you want to start learning about backing up with nvflash, here are a couple links to get your started:

======================================================================
N ) WINDOWS USER NOTES
======================================================================

The major steps and sub-steps in this guide can also be executed from a windows computer. Here are the minor differences when using windows:
  • Download and use the contents of nvflash_windows_2010110500.zip instead of nvflash_linux_2010110500.tar.gz from [RECOVERY] nvflash FULL restore, using either 1.1 or 1.2 based images - [G-TABLET]. This is the same link provided earlier. Note that roebeet's post covers windows setup.
  • windows users will be using batch commands instead of shell scripts.
  • In one step above a script is edited. windows users will edit the batch (extension .bat) file instead. Be sure to use the right syntax for batch files, it is not the same as the script syntax illustrated in this guide. The downloaded batch file could be used as an example.
  • use the windows "command" window (aka; dos prompt, c:\> prompt) where ever a reference to "terminal" is made above.
  • some windows users report usb driver issues when trying to connect to a tablet in APX mode. Here is a place to begin searching for a solution if you have driver issues - Viewsonic GTablet For Dummies - nvflash
  • Here is a guide that may help windows users set up ADB - [STICKY][GUIDE] adb for your gtab (windows)

Edited by djab, 27 July 2011 - 09:43 PM.

  • maultier likes this

#4 djab

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Posted 21 July 2011 - 08:30 PM

.....reserved in case more content is needed in the future

#5 maultier

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Posted 24 July 2011 - 11:10 AM

Thank you, Djab!

I was able 'unbrick' my gtab with your instructions.

A minor issue with the syntax on the nvflash scripts.
'-' instead of '--' in the script.
ie:
shown: sudo ./nvflash –bl bootloader.bin --sync –go
corrected: sudo ./nvflash --b bootloader.bin --sync --go

Bottom line is that after going over all the other gtab 'recovery' posts... this was the one that got me over the hump! Thank you.

#6 djab

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Posted 24 July 2011 - 03:36 PM

Thank you, Djab!

I was able 'unbrick' my gtab with your instructions.

A minor issue with the syntax on the nvflash scripts.
'-' instead of '--' in the script.
ie:
shown: sudo ./nvflash –bl bootloader.bin --sync –go
corrected: sudo ./nvflash --b bootloader.bin --sync --go

Bottom line is that after going over all the other gtab 'recovery' posts... this was the one that got me over the hump! Thank you.


maultier,

I am very glad the guide helped someone else! If you haven't already and feel inclined, please hit the "plus" button on the first post.

PS: did you try the script with "--" (2 dashes)? all of mine had them and they worked fine. just curious if they failed on you.
I know the scripts I downloaded all had "--" (2 dashes. Also, the thread linked below shows the use of "--" (2 dashes) as well.

nvflash man page or command line switches.

Edited by djab, 24 July 2011 - 04:45 PM.


#7 Sm0k3d0uT

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Posted 25 July 2011 - 09:59 AM

Excellent Guide

#8 maultier

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Posted 25 July 2011 - 05:56 PM

maultier,

I am very glad the guide helped someone else! If you haven't already and feel inclined, please hit the "plus" button on the first post.

PS: did you try the script with "--" (2 dashes)? all of mine had them and they worked fine. just curious if they failed on you.
I know the scripts I downloaded all had "--" (2 dashes. Also, the thread linked below shows the use of "--" (2 dashes) as well.

nvflash man page or command line switches.


I edited the scripts by cutting and pasting the suggested script changes from the body of your original post.
That's how I got into the '--' issue. It worked fine once I recognized the problem and modified the script.
No worries.. your instructions were great. Thank you again for putting in the effort to help out!
'plus' is yours.. and well deserved.

#9 djab

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Posted 27 July 2011 - 09:23 PM

Excellent Guide


Thank you! I think at this point I have more time into the guide than the restore :). At least it helped me develop some bbcode skills.

#10 FarSight87

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Posted 02 September 2011 - 01:39 AM

DJAB!
Hi, First of all, this is a great guide, Thankyou.

I am experiencing a massive problem with my gtab at the moment which is detailed here

I followed your guide and i reach the step 4)EXECUTION e)3. At which point my tablet hangs on the screen with "Recovery key detected" "booting recovery kernel image" and never enters cwm. I was wondering if you had any words of wisdom from this point on, as i believe i have a partition problem but cannot enter cwm to fix it.

cheers.

#11 mlaksh

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Posted 29 December 2011 - 04:15 PM

Thanks DJAB.

Your guide helped me really. I was facing the exact issue that you mentioned in the problem statement. Even though I was doing it in Windows XP, thanks to your detailed instructions I had no problem in recovering from the "failed recovery mode".

Happy Holiday and Happy New Year.

#12 falcaraz

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Posted 26 January 2012 - 06:43 AM

I've been up all night trying to get this thing fixed, but still stuck in apx mode. I got to step h-6, followed instructions exactly at h-4 in recovery. But when I reboot it is still stuck in apx instead of booting into Mountain laurel. I waited about 5 minutes at the black screen just in case but nothing.
I managed to get it to boot into Mountain Laurel by using the nvflash_boot script. Should I keep following the steps? I made sure I followed all previous steps to the letter.

I am completely stumped. I figured this guide would work since I was in a similar situation as OP, I bought this tablet already stuck in APX mode and didn't ask the previous owner if it was 1.1 or 1.2.

Any help would be greatly appreciated.

Edited by falcaraz, 26 January 2012 - 06:47 AM.