tried

newfs -S 2048 -m 0 -b 32768 -f 4096 -i $((256*1024)) /dev/rcd0a

with success. fsck says filesystem OK.

without -S 2048 it doesn't work as recorder can't write part of sector.

partitions were already made with disklabel with few tricks


tried

mount -o noatime,async /dev/cd0a /mnt

worked!

df shows

/dev/cd0a     4587470        2   4587468     0%    /mnt


but that's all :((

ls /mnt shows

ls: /mnt: Bad file descriptor


where's a problem still?!