Yeah, I had two players and both were hacked. I tested them with
H2testw 1.4. It turned out that the players only had 1.7Gb and 1.8Gb instead of 16Gb. That caused the problems. Though the seller promised warranty he withdrawn himself from the internet and he disabled his email-account after I confronted him with the testresults. We discovered also that his house is for sale, so a letter to that adress won't work. The only thing I can try now is to send a letter to his work (we know the school where he is working), but the change that we get our money back is very small now.
I wonder if a part of the problems of the players will cease if (I buy and) use an SD card - the players have SD card slots after all. Maybe they will play the video's correctly if I use an SD card of 8Gb (or more).