SE Tool is a very good
SonyEricsson unlock, flash and repair tool,
it has amazing power and ease of use for most of todays SE phones.
The author does some really cool updates to
cover new models and strange hard to unlock models like
epoch models M600, P990 etc.
and A2 models C902, k850, w910 etc.
Again we use this as first port of call for unlocking SE models,