How to mount ufs file system under Debian testing?

In order to mount my /dev/sda4 under /mnt/ufs_mount on Debian Testing , i have tried the following commands (it works fine under Debian Jessie): modprobe ufs mount -r -t ufs -o ufstype=ufs2 /dev/sda4 /mnt/ufs_mount and: mount -t ufs -o ufstype=ufs2 /dev/sda4 /mnt/ufs_mount But i get this error: mount: /dev/sda4 is write-protected, mounting read-only mount: wrong fs type, bad option, bad superblock on /dev/sda4, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. The output of: dmesg | tail : [ 1136.965142] ufs: ufs_fill_super(): bad magic number [ 1255.758946] ufs: ufs_fill_super(): bad magic number [ 2098.945757] ufs: ufs was compiled with read-only support, can't be mounted as read-write [ 2098.946045] ufs: You didn't specify the type of your ufs filesystem mount -t ufs -o ufstype=sun|sunx86|44bsd|ufs2|5xbsd|old|hp|nextstep|nextstep-cd|openstep ... >>>WARNING 2500), lowering kernel.perf_event_max_sample_rate to 79750 **Edit** My sources.list: deb http://httpredir.debian.org/debian/ stretch main deb-src http://httpredir.debian.org/debian/ stretch main deb http://security.debian.org/debian-security stretch/updates main deb-src http://security.debian.org/debian-security stretch/updates main And uname -a: Linux debian 4.6.0-1-amd64 #1 SMP Debian 4.6.4-1 (2016-07-18) x86_64 GNU/Linux How to mount ufs file system under Debian testing?