I used flashtool to unlock the bootloader. I reset the phone but it hung on the sony logo, which was odd. (I have unlocked and flashed around a dozen xperias and this has never happened). I pulled the battery and turned it back on and it boot looped on the sony logo. (left it for several minutes to be sure). Every time it was switched on after that the screen powered on but remained blank.
I flashed the Rage kernel for GB. Turned the phone on and the sony logo came up, went bright, and I got into CWM recovery ;0)
Fast boot works, Flash mode works, Flash tool lets me lock and unlock the phone, flash kernels (rage/X-kernel and Lupus) and ftf firmwares ... S1 tool sees my phone, pc companion updates the phone perfectly, but still no screen.
I read the other ST17i bricked threads here and looked at trying the Wotan server method but the phones date code is not covered, its newer than the ones Wotan cover (maybe an issue?).
I have not idea right now, apart from I have hard bricked it somehow. (searching for 'st17i dead screen' gives a few results from Sony's service forum with similar sounding phone activity, with no resolutions). Searching for bricked st17i all relate to soft bricked devices.
As the phone is brand new, I am not sure about the bootloader issue, is it still covered by warranty? The phones current state is locked and fully updated via pc companion, as it was out of the box.
Any advice and help will be greatly appreciated!