[GUIDE][UTIL][Allview Energy P8] STOCK ROM + TWRP + ROOT

Rooting the Allview Energy P8 (aka Gionee Marathon M5)
Disclaimer: I will not be held responsible for any damages that may occur by following this guide. I'm merely describing the procedure I've used to root my device.
WARNING: THIS WILL DELETE ALL USER DATA FROM YOUR PHONE, so make sure you back that up before going further (the backup described below is strictly related to the operating system and it will NOT save any of your personal data, so make sure you do that yourself).

That being said, let's begin.

Preparation

1. You will need to download the Allview_P8_Energy_0102_V6063.zip file and unpack it somewhere you can access the contents.
2. Install the ADB drivers using the Gionee_Driver_Install_v2.1.0.exe installer (found within the zip file)

Backup
Before doing anything, I strongly recommend that you perform a full backup in case something goes wrong along the way and you manage to brick your phone (I've bricked mine several times until I found the right method).

1. Once your drivers are installed you'll need to connect your phone to your PC
2. Drag down the notification bar and click on the "Connected as a media device" notification
3. Make sure "USB debugging is on"
4. Open "SP_Flash_Tool_exe_Windows_v5.1528.00.000\flash_to ol.exe"
5. Click on the "Download" tab
6. Click on the "Scatter-loading" button on the top-right
7. Select the "Allview_P8_Energy_0102_V6063_STOCK_scatter.tx t" scatter file from the "ROM_Allview_P8_Energy_0102_V6063" folder that was created when you've unzipped the kit
8. Now click on the "Readback" tab
9. Click the "Add" button on the top-left
10. Once the new entry is added in the list below, double-click it and a file dialog will open
11. Now give your ROM BACKUP a name (you will need this later on in case you want to perform an emergency recovery)
12. Select the folder where you wish to place your new backup and click Save
13. A new popup will open allowing us to set the readback block start address - make sure Type: Hex is selected
14. Make sure start address is 0x0000000000000000
15. In the Length box, put this: 0x00000000d7800000
16. Click on OK
17. And now, to begin the readback (backup) procedure, you'll need to click on the Read Back button (top-center)
18. Now reboot your phone (long-press the Lock button on your phone until the Power Off/Reboot dialog appears and select REBOOT)
19. Once the phone reboots the SPF app should start saving the phone memory to file, and your backup is created
20. Once you see a green success message, you can safely turn your phone back on (unplug USB and long press the Lock button until the screen turns on)

Flashing TWRP/STOCK

1. Once your backup is complete, you can go ahead and connect the phone to the USB, making sure USB debugging is enabled.
2. Open "SP_Flash_Tool_exe_Windows_v5.1528.00.000\flash_to ol.exe"
3. Click on the "Download" tab
4. Click on the "Scatter-loading" button on the top-right
5. Select the "Allview_P8_Energy_0102_V6063_TWRP_scatter.txt " scatter file(or the Allview_P8_Energy_0102_V6063_STOCK_scatter.txt if you wish to restore the STOCK ROM) from the "ROM_Allview_P8_Energy_0102_V6063" folder that was created when you've unzipped the kit
6. From the dropdown, select "Download only" (this one seems to have worked for me)
7. Make sure everything is checked (userdata might be unchecked but that's OK because it's empty anyway)
8. Double-check everything and make sure it looks good
9. Now click on the Download button (top-left)
10. The app should now enter into the Download mode
11. Having your phone plugged, reboot your phone (long-press the Lock button untill the Power Off/Reboot popup appears, and select REBOOT)
12. The app should now start downloading the new ROM to your device - PLEASE DO NOT DISCONNECT, STOP THE PROCESS, INTERFERE WITH IT IN ANY WAY, OR EVEN TOUCH THE CABLE, until the entire process is completed - or you might risk damaging your phone :)
13. Wait until the big green Success message appears, and then you can unplug the phone, and Power it on (Long-press the Lock button until the screen turns on)

Let the system boot up (it might take a bit on the first run - needs to cache stuff), then set it up as you would do with a new device.

ROOT

1. Once your setup is complete, go ahead and power off your phone (long-press the Lock button untill the Power Off/Reboot popup appears, and select POWER OFF)
2. Now you will need to enter Recovery Mode by pressing the Volume UP key + Lock key (both at the same time) until the bootloader menu appears
3. Using the Volume UP key, navigate to the "Recovery" option, and the select it by pressing the Volume Down key
4. If this is the first time you enter recovery you might see some Chinese text - move the slider on the bottom to continue
5. Now select your language by clicking the the "Select Language" link on the bottom
6. Check the English option and then click on the "Set Language" button on the bottom.
7. Now simply click the Reboot button, and select "System" in the next screen, and you should be asked if you would like to install root on your device
8. Simply move the slider to the right, wait until it finishes, and you should now have root access
9. Once the phone is turned back on, make sure you don't click on the "Restore OTA" in the System Manager Warning dialog (or it might revert your root privileges - haven't tested that yet).

That's it. You should now have ROOT access and TWRP recovery on the latest STOCK update from Allview (Lolipop 5.1).

I'll be back tomorrow with the procedure on how to build a ROM from a Readback (backup) image.

I'd like to thank Jesus (for miraculously preventing a permanent brick :D), @syserr for their tutorial on how to dice a readback file, @criszz for his guides and support, and last but not least to @mathy007 for providing me with a Gionee M5 stock ROM that I've used to crawl my way out of a nasty brick :)

Good luck!