i always do an NVRAM reset, i did after add it to Delete but no success.Either add it to Delete, or do an NVRAM reset before booting up with the new entry. OC won't override existing NVRAM keys otherwise.
same result, i also tried FF0F0000.
Tnx, it's working now.put in config SIP value to all 0
then from recovery
csrutil clear
csrutil disable
it should work in this way