Flag	Meaning
-C / -D	Compress NSP→NSZ or decompress NSZ→NSP
-F	Re-pad the PFS0 header to 0x20 alignment
-L	zstd long-distance matching
-S / -B	Solid stream (default) or block stream
-l N	zstd level (default 18)
-s N	Block size exponent 14..=32 (default 20)
-o DIR	Output directory
-k PATH	prod.keys (default ~/.switch/prod.keys)
-x	Skip CRC32 check of known keys
-K, -P	Accepted for nsz compatibility, no-op
--keep, keeps update/logo partitions


Example compress/decompress nsp
nszrs -C -B -k prod.keys -s 20 -o ./ game.xci     # block
nszrs -C -S -k prod.keys -o ./ game.xci  # solid
nszrs -C -k prod.keys -o ./ game.xci  # default block
nszrs -C -B -k prod.keys -s 20 -o ./ game.nsp     # block
nszrs -C -S -l 20 -k prod.keys -o ./ game.nsp  # solid
nszrs -C -k prod.keys -o ./ game.nsp  # default solid
nszrs -C -L -o ./ game.nsp

nszrs -C -B -k prod.keys -s 20 -o ./ game.xci              # default (drops logo, empties update/normal)
nszrs -C -B -k prod.keys -s 20 --keep -o ./ game.xci       # keeps everything

nszrs -D -F -k prod.keys -o ./ ./game.nsz
nszrs -D -k prod.keys -o ./ ./game.xcz