We are using RL-USB and RL-FlashFS and ffree function to check the space availabe on the USB drive. With one 4GB drive with free space of 3.37GB, it reports proper free space ie. 0x0d7fad000 But for another 4GB USB Drive with free space of 767MB, it is reporting free space as 0x12000. We have checked the drive with chkdsk command on windows and there are no errors reported. We would like to know what could be the reason of incorrect free space returned by ffree function.