f5 remote issues

hi iv just bought a second f5 for a friend.first one worked perfect but im having issues with the remote on this one.sometimes it doesnt work at all and other times its very "sticky".iv tried a few different firmwares and new batteries but no joy.the weird thing is when im in the menu the response is like lighting going around that.hoping someone else has had this problem,channels work great its just when you try and change them.wondering if its a faulty remote or maybe a cheap clone?was about a fiver cheaper than the first one i bought.thanx

cheers steve il try that first.bloke i got it from said he would send me a different remote or i can send it back to him to see if its got a problem but hoping it doesnt come to that

yeah seems there are 2 different types of f5 with there own seperate firmwares.getting made in 2 different factories apparently

seems iv fixed it after messing around with it.was a bad cline.put it back to factory default,added just the image and channel list and it was a lot more responsive.added the cline and problems started again.did it again with a new cline and its much better.just letting yous know incase anyone has this problem in the future