the tape was recorded on this tape drive under linux with
mt setblk 0 and then
tar -b64 -cvf /dev/st0 <files>

on netbsd

mt setblk 0 - works but turns tapedrive busy light on
tar -b64 -xvf /dev/rst0 gives:

st0: bad request, must be between 512 and 512
st0: bad request, must be between 512 and 512


when trying
mt setblk 512
tar -b64 -xvf /dev/rst0

st0: block wrong size, 64 blocks residual


how to retrieve data?!