USB Mass-Storage hdparm -t

I have a USB2 hard drive and it crashes on hdparm -t /dev/sda.

The Gentoo 2.4 kernel worked perfectly with it (although it only was 8mb/sec).

Is this a known problem? It also crashes on a 'du' to the root dir. Basically anything that pushes the disk.

This is on Kernel 2.6.0-test2 and test3.

I have not tested on previous kernels.

After the crash, I can't access /dev/sda at all.