Go into the BIOS. It allows one to select external boot, and with that, the sequence of bootable devices to search. Once that's up try booting from the USB stick - it should work fine. If one USB port fails, try the other- they have different channels to the MBO, it may be that one USB port is down. I've not tried Sony's BIOS flasher for this. However I can confirm that it worked fine using the Flas*it exe. If you are getting VSS errors I suggest you look at the first post in this thread, it enables one to find the VSS offset location and go from there. The European VSS offset is definitely different to the USA one. Edit. This worked on a friend's Z13 from the UK http://forum.notebookreview.com/thr...aio-z-advanced-menu-in-bios-utilities.795409/.