Want to downgrade bootloader

[3dmonkey]

Ok, now that I've resurrected my 6700 with the original WM5 ROM, I want to downgrade the bootloader from v2.05 so I can get my old 6.1 kitchen on it. Currently I'm running Vista Home Premium SP1 on my laptop.

I've tried following the steps outlined in the post "Stuck in bootloader" but they don't work for me. I've tried so many times to plug in my phone and run mtty to choose USB from the dropdown, but it is flat not available.

Here's what I've done (countless times): Put 6700 in booloader mode. Phone reads Serial at the top and v2.05 at the bottom. Uninstalled Windows Mobile Device Center. Plug phone into USB cable to PC. Immediately the phone screen says USB at top and v2.05 at bottom. Fire up mtty.exe. I can only choose from COM1, COM2, COM3 or COM4 from the Ports dropdown. I've tried each of the COM ports and typed in task 28 55aa but of course it doesn't work.

I'd REALLY like to flash back to an earlier bootloader to get WM6 or WM6.1 on the phone. I had it on before I stupidly upgraded the radio to v1.43.

Any help is GREATLY appreciated!