Set usb flash drive as non rotational drive

I'm trying to optimize the IO schedulers and to use a proper scheduler for rotational and for non rotational drives (different). When I run: cat /sys/block/sd*/queue/rotational I get: 1 <-- for sda 1 <-- for sdb although sdb is the usb flash drive and it shouldn't be rotational. $ udevadm info -a -n /dev/sda | grep queue ATTRS{queue_depth}=="31" ATTRS{queue_ramp_up_period}=="120000" ATTRS{queue_type}=="simple" $ udevadm info -a -n /dev/sdb | grep queue ATTRS{queue_depth}=="1" ATTRS{queue_type}=="none" so there is no such attribute as: ATTR{queue/rotational}=="0" or ...=="1"