I have a strange external USB3-SATA docking station. It says that any harddisk inside has 4096-byte sectors, which makes it unable to normally access 512-byte-sector harddisks (i.e., any disk below 2TB or so).
My workaround was to setup a loop device and lookup the partitions inside this loop device with kpartx.
losetup /dev/loop1 /dev/sdc
kpartx -av /dev/loop1
mount /dev/mapper/loop1p1 /mnt/temp/
# do work ...
umount /mnt/temp/
kpartx -d /dev/loop1
losetup -d /dev/loop1