[vinsca59]

tried all (in fact, they advised me to open a new thread).
I did a lot of testing doing the nvram backup with the SPFT readback function and then flash: it does not work.
I tried to do the same with nvdata: nothing.
I tried nvdata and nvram together: nothing.
I have seen, however, that after having done the root, in the Data folder there is a nvram file with an arrow with a written nvdata next to it and in the nvdata folder I find: md / NVRAM / and other subfolders up to the MP0B_001 file.
this gives me the impression that there are all the folders, but the script that starts the carousel is missing.

Lets do a quick test.
Get the scatter file and unpatched (stock) boot.img then try flashing it using Sp flash tool. Let me know if you still get the buffer error
BTW, it seems the stock roms are signed,  Try SP Flash Tool V5.1532.00 @ https://forum.hovatek.com/thread-13970.html

trying to flash patched_boot.img with sp flash tool the phone does not start anymore (or better: it goes into boot loop), but this situation is easily remedied with the flash boot.img stock.
I tried SP Flash Tool Version v5.1532, but at the time of loading the scatter it gives me error 8417. I have tried all the remedies I could find in the internet for this error, but none of it works.
I am sure that the solution to my problem is there and that once it is found it will seem strange to have not thought about it before.
some people have fun with the puzzle, I like doing this.
what seems strange to me is that after unlocking the bootloader, the wifi and the bluetooth work well, only the imei is missing and also inserting the file MP0B_001 (generated with the ImeiConverter program) in the folder in place of what should be "broken" , it does not work the same.