Frustrated by the lack of resume function

Then from what you are saying it is a problem with the firmware.  Every time I hook up my USB storage device it is a 50/50 guess as to whether or not it actually will recognise the files and if it doesn’t (even though they all played perfectly before the update) I have to eject the storage device, turn off the player, turn it back on again and re-connect the USB storage device and then the files play perfectly fine except  it acts like the files have never been in there before, completely negating the resume function and the rollback to the previous firmware has not fixed that problem.