I WILL HAVE ROOT (Howto that worked for me on Dell Venue 8 7840)

[ShaQ1nJ]

Excellent Guide!

I followed the steps one by one, and now, I have root! Thank you so much for sharing! I gave you a thanks button click too.

I got the Dell Venue 8 7840 as an early Christmas gift (for myself, at Best Buy) and was saddened to learn getting root was (nearly) impossible. I followed various guides (many written this summer, before the latest batch of updates - as of December 2015) but found myself nowhere. Then, I found my answer.

Well, fellow root-wanter, I'm here to tell you it is possible, but it won't be easy.

How I Got Here
Right out of the box, I hastily updated to all the latest firmware updates from Dell. That was my biggest hurdle. So if you plan to do this and you haven't updated the device yet, DON'T UPDATE! Follow the several guides here to get root.

Too late? Already screwed the pooch? Read on.

Generally speaking, you need to do a few steps to get where you want to be. They are (roughly) as follows:

1. Unlock the Bootloader (developer settings change, adb commands)
2. Use the Intel Flash Tool to flash an earlier firmware, thus making your device able to boot a temporary ClockworkMod Recovery (CWM)
3. Use clockwork to wipe the system and cache, then reinstall the OS and SuperUser
4. Reboot and Enjoy!

Here's the long version of steps I took to make this possible:

Getting Started

• As a prerequisite, please install at least the minimum adb/fastboot tools. For first timers, ADB is the Android Debug Bridge, which allows command-line access to system level tools when working with an Android device. It's the backbone of this entire process. Fastboot is a debug mode wherein you can run certain commands on the system, without the presence of an OS. As an Android user, and certainly as somebody who's found themselves on XDA, you should become familiar with fastboot and its abilities. You also can (and should) download the entire set of platform tools (part of the Software Development Kit) as a matter of course.
  
• There are several other tools, firmware files, images, etc. that you will need. I've put all the files I used together in a single zip file, which you can download here:
  Dell Venue 8 7840 Tools and Files (zip)
  * (Thanks to the many contributors on this forum, like toxic_garden, enzymeyllw, mrgardiner and of course xBIGREDDx. Also Chainfire for SuperSU!)
  
• Once you have all your files downloaded, you need to grab the Intel flash tool. My god is that tool a pain in the ballsack. It's also a necessary evil. Give Dell your firstborn, install the damn tool, and let's move on.
  
• Seperately, you will need an SD card with the following files on it: update.zip and UPDATE-SuperSU-v2.46.zip

Ready to Go? Good.

1. First, enable Developer Options in Android. To do that, go into Settings >> About Tablet >> and tap the Build Number a bunch of times. After some vigorous tapping, a toast message (The little gray-oblong, semitransparent box near the bottom) will pop up and tell you "You're now a developer!". Congrats.
2. Go into Developer Options, look a few items down the list for "OEM Unlocking" and enable that sucker. If you were successful, it was the first step toward greatness.
3. If you have to back anything up, now's the time to do it. Because these next steps will wipe your device clean.
4. Install the Intel Drivers if you haven't already, and in Developer Options enable USB Debugging (it's not too far down below OEM Unlocking)
5. Some more drivers will install on your PC, and switch it over to Camera (PTP) mode when you see the selection option in the Notification tray. Eventually, if you played your cards right, you'll see an RSA Security request on your device, asking if you want to trust your PC and displaying a hex address. Click OK.
6. On your PC, find your platform-tools folder (in the Android SDK folder) or wherever you installed the minimal adb/fastboot tools.
7. In this folder, hold down Shift and right-click, then choose "Open Command Window Here" (alternately, go to the Start menu, type cmd and right-click "Run as Administrator" then navigate to your folder with adb.exe and fastboot.exe in it.)
8. Cool, take a breather. How are you feeling? Good? Good.
9. In the black window, type adb devices. You should see a string of numbers or numbers/letters and something like 'unauthorized' in the list. If it's blank, the ADB drivers are not installed properly. Go to your device manager, find anything with a question mark/yellow icon that looks like intel or android or moorefield, and install the drivers manually. You can search XDA if you get stuck on this step.
10. Back in the black window, type: adb reboot bootloader
11. Your device should immediately black out and, after a short while, go to the bootloader menu.
12. From here, go back to the black window and type: fastboot devices
13. You should see another set of numbers/letters and a word after. As long as you see something, you're golden. If it doesn't show up, you may need to double check those drivers. Another set of drivers will need to install for your device to be seen in this state. Just stick with it, you'll get there.
14. All good? Then type fastboot oem unlock
15. You'll get a warning, but just continue on.
16. Once unlocked, it's time to flash new firmware. Note: For me, this was absolutely the biggest PITA step. The tool was written with virtually no instructions. What follows is how I got it to work.
17. While you're still in the bootloader menu, you should see confirmation that your device is unlocked. YAY!
18. Use the menu to boot the device normally. Note: All your user data is gone, so your tablet will act like it's brand new again. Skip through as much BS as you can and get back to the home screen of your tab. Go to settings, and re-enable USB Debugging like last time.
19. While that's happening, go to your PC and fire up the Intel Phone Flash Tool. (Nice name, Intel.)
20. Load up the firmware folder "Dell_Venue_8_7840_Lollipop_5.0.2_qs_rd_opensource-blankphone-userdebug-1397", and specifically choose from the dropdown to flash the file: flash-DDO_BB.xml
21. If the tool thinks your device is not connected, that's okay. If the tool thinks your device is connected, that's OK too. Don't sweat it.
22. With the tool still running, as soon as its connected (allow Android Debugging, change to PTP or what have you) hit the Start to Flash button.
23. It will try about 100 times to find your device (you can see a little console log at the bottom of the tool) ... while it's searching, hold the power button on your device and POWER IT OFF. (Yes, off. Counter-intuitive, I know.)
24. As it powers off, it will enter some quasi-dream state that Intel dreamed up that will allow it to flash the firmware. Give it a bit of time, and eventually the firmware will flash successfully. HOORAY! You just paved the way for CWM.
25. Now go back to the folder of files and tools I told you to download, and find the folder "IntelAndroid-FBRL-05-16-2015-PTR" (alternately, search on XDA and find that tool yourself)
26. Load up the tool, hit accept, then choose option T4 (not T1-3, T4)
27. If you were successful, it will slowly begin copying over files and having its way with your tablet, and eventually some little white text will appear on your Tablet screen. Soon, ClockwordMod Recovery will start up.
28. From here, go to Mounts and Storage. Make sure /system is not mounted, and External SD is mounted. Wipe the /system partition, just to be sure. And again, make sure it's not mounted.
29. Go back to the main CWM screen, and choose "install zip from sd card", and then the option for the external sd.
30. Find and flash the update.zip file (this will give your cleared out tablet Android 5.1)
31. Now find and flash UPDATE-SuperSU-v2.46.zip
32. Go back to the main menu, and Wipe Cache Partition.
33. Back at the main menu, Reboot System Now.

If all went well and I didn't totally screw up this guide, your newly rooted tablet should boot up. It may appear to be stuck on the Dell loading screen a while, but it's not. Give it time, and Lollipop will come right up.

From here, download SuperUser and BusyBox from Google Play, if either of those things aren't present on your tablet. Now take advantage of Titanium Backup to remove all that unwanted crapware, and Greenify (at least) to keep those pesky apps at bay.

Enjoy! If this worked, please let me know. As I said, this is what worked for me - but everybody's situation is different, and I'm sorry if this did not work for you. Obligatory I am not responsible if your device bricks, dies or otherwise craps the bed. Use this guide at your own risk.

Some threads that helped me through, increased my sanity, and eased my upset stomach:
Toxic_Garden's Guide: http://xdaforums.com/showpost.php?p=64391058&postcount=16
Mr Gardiner's Guides: http://xdaforums.com/showpost.php?p=62833258&postcount=4, http://xdaforums.com/dell-venue/general/7840-stuck-bootloop-bricked-t3178937
Enzymeyllw's Guide: http://xdaforums.com/dell-venue/general/7840-succeed-to-unbrick-t3205024
Insight from xBIGREDDx: http://xdaforums.com/dell-venue/general/venue-8-7840-developer-files-posted-t3144232/page4

A side note: a few of those unbricking guides tried to have me use the adb shell to send the system image to the device, but I didn't find that necessary. Just flashing update.zip with CWM got me far enough along to get the tablet running. I'm not sure if that will come back to bite me in the ass, but hopefully not.

 

[Illux]

So this does work with 5.1 Stagefright? Or is the version we´d install using that instruction vulnerable?

 

[exbee]

Hey so I followed this guide and everything worked fine, no issues. The only thing is now alot of apps I was using arent working anymore due to having to lower the firmware. If i wanted to revert the whole root process and go back to the latest firmware, would i just update the tablet the normal way you update the system software?

 

[StefanoAS]

I got the Dell Venue 8 7840 as an early Christmas gift (for myself, at Best Buy) and was saddened to learn getting root was (nearly) impossible. I followed various guides (many written this summer, before the latest batch of updates - as of December 2015) but found myself nowhere. Then, I found my answer.

Worked perfectly for me.
Very very (very!) useful and stupid-proof guide, thanks a lot indeed
:victory::victory::victory::victory:

 

[silverhand1990]

Thank for your guide. I followed it and flashed my china kitkat version successfuly. After flashed, my tablet has updated over OTA for many times (maybe 5 or 6 times until now), is that normal?. There is another problem, it always displays fastboot screen everytime it reboots, so i have to press power button to choose normal boot. How can i turn off this.
Thank for your help!

 

[johnsag49]

Yep, I think so.

 

[johnsag49]

Thank for your guide. I followed it and flashed my china kitkat version successfuly. After flashed, my tablet has updated over OTA for many times (maybe 5 or 6 times until now), is that normal?. There is another problem, it always displays fastboot screen everytime it reboots, so i have to press power button to choose normal boot. How can i turn off this.
Thank for your help!

silverhand1990 - i'm not sure about that one, you technically should not be booting into fastboot each time you reboot your tablet. But I'm wondering if this is a fastboot-like-screen that's simply telling you that your bootloader is unlocked? Android has that functionality built in - it basically warns you that your device *could be* at risk for attack - the same thing happens on my OP3, but I ignore it.

 

[mttrwlnd]

Hello. Just managed to obtain a Dell Venue 8 7840 off eBay. Before being sold, it was updated to the latest update (5.1 w/stagefright fix), and factory reset. This seems to be the best guide I can find. Will it work under my circumstances?

 

[gimlet72]

Hello. Just managed to obtain a Dell Venue 8 7840 off eBay. Before being sold, it was updated to the latest update (5.1 w/stagefright fix), and factory reset. This seems to be the best guide I can find. Will it work under my circumstances?

I have had my tablet for a while updated to the latest software and was too lazy to root. I just followed the instructions today and it still works

 

[klm2349]

Back to stock

How do I get stock recovery and firmware back on this tablet. I have tried everything I know how and scoured xda and the internet looking and can't find it.

 

[chang69]

I got the Dell Venue 8 7840 as an early Christmas gift (for myself, at Best Buy) and was saddened to learn getting root was (nearly) impossible. I followed various guides (many written this summer, before the latest batch of updates - as of December 2015) but found myself nowhere. Then, I found my answer.

Thank you for writing this detail manual. It worked very well for my Dell Venue 7840 till every step.

Thanks gain.

 

[NPboeuf]

I'm stuck on step 23, every time I start the flash it says "Qt: Untested Windows version 10.0 detected!" and then fails while still at 0%, is there any way to fix this?

 

[rolo888]

Adaption on step 23

Hello just rootet my Venue 8 with your instructions thanks a lot.
It seems however that point 23 needs a slight adaption. The Intel Flash Tool now is called "Intel Plattform Flash tool" and at the time I'm writing this the procedure to enter the "dreamlike state" seemes to have changed. So the Adapted Step 23 should look like this:

"23. It will try about 100 times to find your device (you can see a little console log at the bottom of the tool) ... while it's searching, hold the power button on your device and POWER IT OFF. (Yes, off. Counter-intuitive, I know.) AS SOON AS THE DEVICE SWITCHES OFF PRESS THE POWER BUTTON AGAIN FOR ONE SECOND TO RESTART."


After I found that out your tutorial worked like a char. Thanks again!!
Rolo

 

[izumi1337]

Hi there, I need some help with step 14:
All good? Then type fastboot oem unlock
And then it says
E:\Program Files (x86)\Minimal ADB and Fastboot>adb devices
List of devices attached
5C400CHA01 device


E:\Program Files (x86)\Minimal ADB and Fastboot>adb reboot bootloader

E:\Program Files (x86)\Minimal ADB and Fastboot>fastboot devices
5C400CHA01 fastboot

E:\Program Files (x86)\Minimal ADB and Fastboot>fastboot oem unlock
...
(bootloader) Checking unlock authorization.
FAILED (remote: couldn't change state)
finished. total time: 0.281s


I'm on 5.1 and followed all steps precisely
_________________________________________________ Edit

Also tried another computer - same thing with one exception:
5C400CHA01 unauthorized instead of device

 

[NPboeuf]

Will this method for rooting work on ubuntu as well?

 

[lestatab]

Hi, i always flash cm rom on my phones (Nexus 4, lg g2, z1, lg g3) and the steps are more o less the same: unlook bootloader, install custom recovery, flash root or new rom. In this case (dell tablet), its necesary downgrade o flash recovery? Can i flash supersu from adb whith original recovery and bootloader unlook?

Edit. Well, after a little of search on google, i understand that is not possible, but i dont know exactly why not, whatever, i followed all the steps and works great, my 7840 is rooted and until now works great, thanks a lot!

 

[horsti2010]

Hey guys, I know this thread is dated.... Anyway, I was following the procedure again because I needed to re-flash the system of my 7840 after a while. And I thought "what about flashing Magisk instead of SuperSu" to get all the convience like passing Googles safety net flawlessly And yes, it works like a charme. So my suggestion is to replace the Update-SuperSu-v2.46.zip file with the latest Magisk zip-File from this XDA-Thread. Just follow the guide in the first post, but whenever it says "SuperSu...zip" just use "Magisk-v16.0.zip" (or later Magisk versions that appear in the future) and flash it instead in the tethered CWM.

You will find the Magisk Manager after the first reboot and can use it to grant other apps like Titanium Backup or Adaway root access, etc., but also hide root from apps that check saftey net. See the Magisk thread if you need further instructions on how to use Magisk to hide apps. For me, it works perfectly and it is now possible to use some more apps! It is at least something new or a nice alternative that e.g allows you to use some banking apps, sports apps and games (not my business though).

Disclaimer: I also tried to apply the Stagefright Update which has always been impossible to install smoothly after gaining root. I thought that Magisk with its systemless procedure might allow the update to get installed. But it fails like always. Again, it also fails with SuperSu, but still we have the advantage of Magisk over SuperSu (safetynet, etc.).

 

[CatDiablo]

I Need Help! stuck on step 25

I got through step 24 and flashed successfully, but when i try to use the fastboot tool in step 25, it doesnt give any device status as being connected, or anything like that. It says ('""' is not recognized as an internal or external command, operable program or batch file.) at the bottom of the screen and when i try to use option T4 it just closes the window and nothing else happens.
If I type fastboot devices in cmd I see my device. Can someone help me, Im a complete noob to all of this so i need clear step by step help. Thanks.