I upgraded to hplip 3.17.10+repack0-5 (as part of upgrading to Ubuntu 18.04 LTS) and the problem's gone away. This package depends on libsane-hpaio 3.17.10+repack0-5 , which comes with /usr/share/hplip/data/models/models.dat , and the hp-* commands are able to find it:
I upgraded to hplip 3.17.10+repack0-5 (as part of upgrading to Ubuntu 18.04 LTS) and the problem's gone away. This package depends on libsane-hpaio 3.17.10+repack0-5 , which comes with /usr/share/ hplip/data/ models/ models. dat , and the hp-* commands are able to find it:
$ hp-setup usr/share/ hplip/data/ models/ models. dat", {st_mode= S_IFREG| 0644, st_size=1178923, ...}) = 0 hplip/data/ models/ models. dat", O_RDONLY) = 23
stat("/
openat(AT_FDCWD, "/usr/share/
oversight on my part not to come back to this bug and say "fixed in a newer version"