I have already installed a9lh through otp-less mode, but I want to go back to 2.1 to dump my otp. Following all the security tips of this version of Plailect's guide: "https://github.com/Plailect/Guide_RedNAND/wiki/Part-4-(2.1.0-Downgrade)", is there any other things I could do to prevent a brick? What should I do after dumping my otp.bin? Just restore my 9.2 SysNAND backup? Also, exactly in which step do I actually get my otp.bin?