PSP 3002 Boot Problem

[Satcity]

Hopefully someone can shine a bit of light on what the problem might be with a PSP 3002 I have that belongs to my son.

It starts to boot getting as far as the wave on the display but then it stops, the XMB doesn't appear. It is running official firmware, but not sure what version.

Any help would be most appreciated,

Thanks in advance

Paul.