Iriver clix gets static-y after a few minutes
I am sorry to hear that your Iriver Clix Gen 2 4 gb video player recieves enormous amounts of static that makes it unaudible after a couple minutes.
I see that you have eliminated one of the factors of static by upgrading the firmware, but unfortunately the firmware is only related to booting up, and loading your movies/music.
If the static is coming from the speakers, you may not be able to fix it, unless you open up your Iriver Clix, which I recommend you not do, due to that it will void your warranty. The Static may be caused due to excessive geforce or impact to your device, causing the wire's to be loose. If the static is coming from the speakers, I would recommend you to return it to the manufactuer or return it back to the store.
If the static is coming from the 3.5 mm plug, try a different pair of headphones or earbuds, make sure it is fully plugged in, I would also recommend you to return back to the manufacturer, or return it back to the store.