tm9100 booting problem

[uk nurnberg fan]

I am having real trouble getting my box to boot up correctly. It stops a minute or so after the first image picture comes on the screen. I have tried doing factory reset - same result. Have reflashed the image via serial - same result. Have tried different image - same result. Have tried noboot image - same result. I am thinking that I must be doing something simple incorrect or in the wrong order. Any help would be greatlt appreciated.