yeah in my experience t doesn't make a difference if you use the leading 0x or not so that's unlikely to be the issue. the problem I had was if you enter the memory address before clicking to select MMC/SD it resets the address to 000000.
if you're not getting anything on screen it couldn't hurt to reflash the boot loader. I think Hawhill posted one. if no it I've got one at home I can email you when I get back (next month
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