How to fix secure boot devices DA file error

[suji]

I backup my current stock rom using Wwr and SP flash tool but SP Flash tool giving DA error, So I used the DA file given in the site but SP flash tool not taking it and says to Re-select DA file. So I cant use Readback in SP flash tool. First I faced the error 0x00010001 and tried fix by your error fix but at last end with error 0xC0060003.
In the next I used Miracle box(crack because older version does not support, I used v3.17) And it takes the secure boot DA file given by this site. So I backed up full stock rom, but all the files are a single .bin extension file. Therefore I backed up as scatter, but all img like boot.img recovery.img are in the boot.bin and recovery.bin . So I cant extract the boot.img and recovery.img from .bin files. When I try to flash the backup created by miracle box, it exits easily.
So please help me to extract boot and recovery image, because I want to build TWRP and to grant root access(Bootloader locked-Tried all the possible way like fastboot, adb shell, mtk-su, but all are failed).
My device info:
Vivo Y81(1803)
Software version : PD1732DF_EX_A_2.70.7
Android ver. 8.1
Chip: Mediatek Helio P22
MT6762= From cpu-Z app
MT6765= From miracle box
Check screenshots:

[X3non]

...

if bootloader is locked then i'm afraid you won't be able to root
also .bin files are the same as .img , simple rename the file and change the file extension

[suji]

I flashed custom recovery ported using your auto port tool as well as AIK tool, In auto port tool I got a message that Dm_Verity found, need to flash patched boot image and I flashed recovery and boot image but all end up in continuous reboot of vivo logo with red state title but fixed it by flashing stock images.

It allowed me to flash eventhough the bootloader is locked but caused bootloop, help me to get root acess.
No bootloader unlocking available

[X3non]

I flashed custom recovery ported using your auto port tool as well as AIK tool, In auto port tool I got a message that Dm_Verity found, need to flash patched boot image and I flashed recovery and boot image but all end up in continuous reboot of vivo logo with red state title but fixed it by flashing stock images.

It allowed me to flash eventhough the bootloader is locked but caused bootloop, help me to get root acess.
No bootloader unlocking available

if bootloader is locked then there's no need to try forcing root, the device will go straight to red state
you can try the method @ https://www.hovatek.com/forum/thread-19578.html ; if none of the 3 commands is able to unlock bootloader then only the oem can assist you in unlocking the bootloader

[suji]

But how oem will assist me? tried all the fastboot commands from your site but says remote unlock failed, error:0x7000
nothing is there in google, everyone talked about vivo y51l , but mine vivo Y81 and I tried all vivo unlock commands but it didn't unlock my device bootloader
Please sir help me to get root.

[X3non]

But how oem will assist me? ...

only the oem will know what or how to unlock such a device
you can try searching for hidden commands using the guide @ https://www.hovatek.com/forum/thread-21403.html ; see if you find anything useful

[suji]

But how oem will assist me? ...

only the oem will know what or how to unlock such a device
you can try searching for hidden commands using the guide @ https://www.hovatek.com/forum/thread-21403.html ; see if you find anything useful

I dont have root acess and even temp root too..

[X3non]

I dont have root acess and even temp root too..

for firmware backup, you don't necessarily need root access, see https://www.hovatek.com/forum/thread-21970.html

[suji]

I dont have root acess and even temp root too..

for firmware backup, you don't necessarily need root access, see https://www.hovatek.com/forum/thread-21970.html

But at any cost I want root, I want to build custom recovery and roms

[X3non]

But at any cost I want root, I want to build custom recovery and roms

in that case, you should consider changing device to one that supports unlocking it's bootloader