NEBULA6.9_V46_MT6577_V1.26 FIRMWARE :
NEBULA6.9_V46_MT6582 FIRMWARE :
FIRMWARE FLASH TOOL WITH SUPPORT
The above links should be everything you need,
from what i can gather, your device comes in two different CPU Models, a MT6582 and an MT6577.
You'll need to identify your exact model before attempting to "DOWNLOAD" the system partition only.
SP Flash Tool has a few different options when you flash a new firmware, The first being DOWNLOAD, the next is FIRMWARE UPGRADE ...
You should never use FIRMWARE UPGRADE, EVER ... It is specifically for changing the entire android partition scheme, meaning that you will loose alot of partitions that aren't included in online firmware's such as the NVRAM, among other partitions, that hold your IMEI number and modem information, these partitions can not be restored after FIRMWARE UPGRADE and will need to be rebuilt by another software, however most imei, nvram repair tools no longer work on many newer MTK device's.
HOW TO USE THE FILES ?
• Download & Extract the correct firmware
• Download / Extract / INSTALL SP Flash Tool v 5.16+ ( link is 5.17 )
• Open SP Flash Tool
- select load scatter
- find and select the MT65xx_Android_scatter.txt file from the extracted firmware
- unselect all partitions except system to be flashed
- select DOWNLOAD as the method of flashing
NEVER SELECT FIRMWARE UPGRADE !!!
• Turn Off your device and remove the battery
• Put the battery back in, and DONT turn it on.
• Place a USB cable into the computer, and then select START or FLASH "I can't remember the exact text"
• NOW Quickly insert the other end of the USB into your switched off device
• You should see the it loading and changing colors
• After it's finished, a big green OK sign will pop up if it was successful
NO GREEN OK SIGN ?
Usually this is caused by a mismatched firmware, however their are a few different errors that may occur..
Incorrect Scatter File
Partition Scheme Changed in Firmware
Sometimes you'll get the wrong error response for the wrong reason, I'll explain.
First we need to look at the scatter file with a non destructive text editor like notepad++ , Wordpad and Notepad will change line endings to a different format and destroy a good scatter file, so don't use them.. and if you do, don't replace or add any line endings, like pressing Enter.. at all.
Ok so let's say i change my scatter file to say it's for an MT6578, now SP Flash Tool will say Chipset Mismatch, instead of incorrect scatter file...
If i correct the chipset in the scatter file to correspond with my device, it'll bypass that problem with chipset mismatch, but i can only do this if I'm sure that the firmware is designed for my device...
Usually with a working device, you can cross reference the scatters partition scheme by looking at your devices partition scheme...
on your device or adb, you'd use the command
adb shell cat proc/partinfo
and then crosscheck the partitions are correct.
In your case, their are methods of checking SP Flash Tool log files to find the partition scheme mismatch information, that'll include your devices scheme, and the scatter files scheme ( as to compare them )
Their is many ways to fix any flash errors, but using FIRMWARE UPGRADE is not one of them !
If you must try, use notepad++ and edit the scatter file, it's the only way for a successful flash...
Even if the system partition is from a different firmware with the same Android Version and Kernel Version and bit version x32 or x64, it can be used... This is because it purely contains system software that is designed for the corresponding hardware.
All other thing's like graphics drivers, modem drivers etc, are stored in separated partitions from the system partition.
Anyway, good luck on your endeavor. I have had lots of valuable lessons breaking my MTK's and needing to do exact clones to get it back ( not recommended ) ... and i hope some info here will help save you a few bucks, while also stop you from making the many mistakes that i have.
Every new Flash attempt, requires removing the USB cord from your device and then plugging it back in for a new connection to the preloader.
HANDY TIP :
I wish someone had of told me this years ago, but i know that it's kept pretty quite for good reasons, but here's how to put SP Flash Tool into Advanced Mode
1 - Open SP Flash Tool
2 - Hold CTRL + ALT + V and release
You should see it change to Advanced Mode in the title, this allows full read write access to every single partition on your device, so be careful !
You can now READ your device and WRITE back to it at any partition sector, this allows you to ignore the devices partition scheme, as with FIRMWARE UPGRADE, but without the Automatic removal of all sectors.. meaning you can still flash a file to an exact location represented as hex start position and length of image to flash ( you essentially become the scatter file ).