nice thanks for the help i hope i can do it? i have a question i have a backup of my sysnand its possible then to restore? when if bricked
You restore it at the end of the process.
For the most part, you're tampering with the emuNAND to downgrade it to bricked 2.1, backing it up, unbricking it, and then using that unbricked emuNAND backup to restore to sysNAND.
You won't be touching sysNAND until you restore the unbricked emuNAND backup to the sysNAND.