[gwynevans]

The "Universal Flasher" involves an SD-Card-based utility script to allow you to do various things with the device, but the main use of it involves creating an image by merging the device existing frmware with some tweaked files, then flashing the new image.

As Igorsk says, one of the other things it can do, is to set the device into a "Firmware Update" mode, after which the Sony Updater executable should be able to reflash the device to the V1.1 firmware.

If you've done both those two things, with no errors, and it's still showing 'Demo', then I'm not sure what the best approach might be as it'd probably need some form of 'custom' solution.

[Edit] You don't need a large SD card - You probably only actually need a few MBs, so I expect the smallest you can find these days would be ample!