Thank for the advices!
So, I will connect my USB to TTL board using 3.3v for the oscilloscope pcb.
@YetAnotherTechie, thanks for the help. I am reading all the posts in this sub since a week ago, and i am learning a lot! But I do not remember anyone saying how can we backup the NAND, or am i missing something? What i understood was that by the serial connection we can read the system doing the boot up, and uploading new firware files, am i wrong?