[Fuhu Nabi 2] aicjofs:
Symptoms​

The classic symptoms of the issue are at some point the Nvidia Dreamtab will stop booting and hang at the Dreamworks characters screen and never boot any further. The frequency ranges from once a month to a year. You are able to factory reset and the issue goes away for some periodicity and then returns.

NOTE: If you recently bought a new Nvidia Dreamtab and you have this character freeze right after doing the OTA then this probably isn't the issue, I am working on a different fix for that problem in this thread. If however this solution does fix your issue I'd like to hear about it.

Background​

The tablet uses the linux ext4 filesystem. The Dreamtab kernel requests a filesystem check every 20 partition mounts(typically during reboots) or when the files system is marked dirty(the tablet is hard powered off, or some other glitch). The tablet is missing the fsck binary which is the filesystem checker similar to what you might have seen in windows with chkdsk. Without this file the tablet can not check filesystem and the kernel waits indefinitely for that to happen and your tablet sits and the Dreamworks characters.

Solution​

Temporarily boot to a program(TWRP) that can install the filesystem file on the tablet. To temporarily boot to TWRP the bootloader must be unlocked. The unlock procedure requires erasing all information on the tablet which isn't an issue if you are currently experiencing the problem as a factory reset was the only way to recover anyway. If you have a working tablet and want to apply this fix you should find a way to backup your files prior to attempting this. To better understand how the low level Nabi functions this should be required reading and will help better understand what you are doing. http://xdaforums.com/nabi-2/general/nabi-information-t3229119

Procedure​

Only for Nvidia Dreamtab NV08B. Use this at your own risk, your warranty is void. You will lose all personal data on the device

Link to video Youtube video installation

1) Down load the drivers.

-- There are 3 popular options included in the link from above in the driver section of the Nabi General Information thread. Have them handy for the next step.

2) Download TWRP recovery.

-- The file is attached at bottom of post. DTTWRPinstaller300.zip

-- Note: You can automate some of the bootloader unlock and installing TWRP steps below with the install.bat file if you have a working Nabi.

3) Download the fsck patch.

-- The file is attached at bottom of post. NV08B_FSCK_PATCH.zip

4) Reboot to fastboot protocol

-- With Nabi powered off press and hold the power button and the vol + button until a small menu(bootloader menu) appears. Quickly release both buttons or the tablet will start booting normally. Using the vol- button to highlight the fastboot protocol(2nd option from top) and then press the vol+ button to select it. Note: Depending on if the drivers are installed the screen will change or stay the same.

5) Verify drivers installed or install drivers.

-- Open windows device manager. On Windows 10 type "device manager" in to the Cortana search bar. On other versions open run by pressing the "windows key" in lower left of keyboard while also pressing R key. Then type: devmgmt.msc

-- If you have "Android Device" and it's sub menu says bootloader/fastboot then you are set up. If down by "other devices" you have an unknown device then you will need to install the drivers from the selection and download you made from reading the Nabi General Information thread.

6) Unlock the bootloader

-- This step will ERASE ALL information on the tablet.

-- Unzip the DTTWRPinstaller300.zip to a location of your choosing. If you use Windows built in unzip utility make sure you check the box that says to open when unzipping is complete.

-- Hold the shift key on the keyboard while right clicking on the "files" folder. Then select "open command window here"

-- At the prompt type:

fastboot oem unlock

Note: You need to move quickly to the tablet and do the next step as there is a timeout

-- On the tablet it will ask if you want to unlock. Using the vol- key select "yes" with vol+ or pwr. If you do this properly in the command window on your computer it will tell you it is erasing the device.

7) Temporary boot TWRP

-- I can't remember if after the bootloader unlock if tablet is at fastboot, or if you have to power off the tablet and do step 4 again. I think you can just proceed.

-- At the prompt type

fastboot boot recovery.img

8) Get the patch file on the tablet

-- Option A: There are a couple options for this. Check the file explorer on your computer. If you see t8400n as a device you can just copy and paste the NV08B_FSCK_PATCH.zip to the internal storage by copy and pasting in windows. Go to step 9.

-- Option B: Insert a microSD card in your computer and copy the NV08B_FSCK_PATCH.zip to your microsd card and insert the sdcard in the tablet.

-- Option C: If the t8400n does not show up on your computer then you will need to transfer via ADB. This will require you to setup the ADB driver like you did for fastboot in step 5. Now in sub Android Device in Device Manager you should see ADB, if you don't install driver.

--Copy the NV08B_FSCK_PATCH.zip to the "files" folder where you extracted DTTWRPinstaller300.zip. It should be in a folder with adb, fastboot, AdbWinAPi, etc

-- At the command prompt type:

adb push NV08B_FSCK_PATCH.zip /sdcard

9) Install patch

-- In TWRP on tablet click the install tab. Generally you will now see the NV08B_FSCK_PATCH.zip if you picked option A or C. If not navigate to the sdcard folder. If you picked option B navigate up a folder and find external_sdcard folder and look in there.

Note: For external_sdcard it may be necessary to exit to TWRP main menu and select mount tab and make sure Micro SDcard is checked.

-- Once you have found the NV08B_FSCK_PATCH.zip from inside the install tab you can select it and then swipe to install. You should get verification it completed normally.