X7 wont flash

Hi All,
I have a problem with an Opticum X7 HDXts703p. While scanning sat channels it locked up for some strange reason. if I power ccycle the box it now displays 'BOOT' and then 'On but nothing else happens. I tried to reflash it with sw 1.3.81 but it goes as far as 87% and stopps.Has anyone any idea.
Thanks in advance.

Thanks for your reply.
Yes I am using the rs232 cable. It stops at 89%.