okay, this is how you're gonna do it via SD flashing...

What you need:
SD Card w/ Reader (not cradle)
XDA Tools
Thats It!

1. Go to http://lumpistefan.dyndns.org/ and click on PPC 2002...

Under "select your base rom" select 3.14.40 ENG T-Mobile US if you have Tmobile, if you have at&t, choose this one A.20.17 ENG Siemens ..if neither don't worry about it...either one..

In the "Select your own Operator config" select No Autoconfig data..

There's a lot of cool stuff in there, if you have time to try them out, but for now thats all you need for the sake of recovering your pda...

2. Once you selected your options, the last part under "how would you like your rom?" click on zipped nk.nb1 (SD-card flashing)..

3. http://wiki.xda-developers.com/wiki/XDAtools ..... download xdatools, this is what copies your operating system onto your sd card so you can get it on your pda...

4. Follow those instructions, but I'll simplify it for ya...

Once xdatools is installed, go to start --> Programs --> and then wherever OSImageTool.exe is...open that up..and then there's two text bars, the top one is where you open up your nk.nb1 (by the way, its going to be in a zip, and you're going have to extract it), and then the bottom text bar, just click on the arrow, and then point to where your SD card is..

Once you get it onto your SD card, put it in your pda... To load up wallaby, hold your top left power button (the one you use to put turn off the screen), and while holding that, press the soft reset button on the bottom left (the side of the green phone)...Wallaby will automatically recognize that you want a new OS on it, just hit the center of the cursor to download it...takes about 5 minutes, after that, you'll be set...

Good luck..