Originally Posted by DonKapselo
Just try to read flash, it's safe. I can bet You will get error 0x7D4 or 2004 (depend of version of flashtool). It's extra locked for sure. Btw. why You need original recovery to start TWRP? Maybe You mean that You need it to compile TWRP for this tablet model?
The easiest way to port TWRP is to get it from another device with the same chipset and cpu. I did not wanted to prepare a toolchain/crosscompiler and start from the beginning to compile TWRP. So I took a TWRP from another tablet (DOOGEE_X6pro_Android6.0_20160707). Since it has a recent version of TWRP and is compiled for android 6.
Then all you need is to replace the kernel in this recovery, so we are booting with the kernel for our device. I needed the kernel from our original recovery for that. Then I've touched some files inside the recovery, fixed the fstab and default.prop and repackaged the recovery image.
This is the easiest way to port the recovery IMO. Took me 15-20 mins with all the testing.
This procedure work for any recovery, not only TWRP.
I guess, I could have dumped the original recovery from the device, but since I was looking for custom recovery for some time, I found the dump in the russian forum and downloaded it. So when I decided to port TWRP, I already had the recovery from the dump.