Hangs at Bootloader

[dms05]

I've just acquired an HTC TyTN running WM5. I tried to add HardSPL to it ahead of upgrading to WM6. I've never done any of this before.

I followed all the tutorials on using Vista/WMDC and new drivers, but as I already use an HP 514 I had most of these installed.

When I ran the HardSPL RUU Wrapper it seemd to go OK, I completed the recommended ticks in boxes. However when it was all finished the HTC TyTN reverted to the bootloader and showed the unchanged original version still installed. At that's as far as the boot process goes.

I've tried soft and hard reset. Hard reset offers the options of full reset by pressing R on the keyboard and the screen goes in a tiny fraction of a second to the Complete press Spacebar. But when I press Spacebar I just get returned to the bootloader screen.

I've removed all cards (SIM and SD). I've left the battery out for a couple of hours (it's the only way to turn the device off).

Any ideas how I can return to WM5 as originally installed?

Or have I a brick?