Yes i have used the update tar Generic file. It is found , appears to unpack successfully and then PC reboots and then keeps rebooting.
I have tried img.qz generic also via usb created with rufus. Reads file from usb boot appears bottom lefthand corner of the screen. Then as with the other method just starts get to the same position and then restarts.
As i said in a previous post all Openelec 6.03 stable and alpha 7.0 beta 1 and beta 2 worked perfectly but alpha 3 had exactly the same problem i am having now.
Something has changed between 7.0 beta 2 and current releases not sure what but it is a shame.