badblocks utility keeps reporting "invalid last block"

I'm trying to run badblocks on a drive with a single partition. The drive contains a FreeBSD file system on it. I boot up using a Linux live USB drive. The drive is unmounted. The output of fdisk -l is: Device Boot Start End Id System /dev/sda1 * 63 976773167+ a5 FreeBSD So I run: # badblocks -v /dev/sda1 And it says: badblocks: invalid last block - /dev/sda1 I can't find any useful information about this. Am I using the badblocks utility correctly here? Or is this an indication that something is wrong with the drive?