If you got error during flash your blackberry Unable to reconnect to the device during a multi-stage load operation you should be type START to out cal mode then you will see error 507 , after you need to update os again the blackberry to done your job.
I only see a no battery icon all the way. I press S.T.A.R.T but it did not appear error 507 as what Ramjan said.
Regards
GFI