The OS-72HR was a great little player (interesting how now its little and back when it came out everyone though 4.3" was huge).
TWP i think its the USB port that might be damaged or loose, this could also be the cause of why you need to reload the firmware, if the unit is not properly disconnecting it can screw up the firmware. Not sure if its a matter of checking the pin or resoldering the port but you should check the next time you open it up.
I would prefer to bring back the old line than do these tablets anyday, there was actual style and things to be interested about the old players, not the same with tablets.
I miss the old days, when the new chips/features came out. It was a blast. Tablets/Android bore me, to be honest.
Raz, I just use a micro SD now for it. Load my movies on it, insert, no problems. Easier than messing with the USB. However, if I do ever take it apart again, I'll give it a look.