Thank you both ever so much. the solution for anyone in the same problem is at the bottom of this post... that manual link is the business! THANKS A HEAP!
** To Format Internal Flash to new Custom SLC-3000 ROM **
** Note You will lose all the data on your Zaurus!**
1. Make sure you have the updater.sh and initrd.bin files in the root of your cf/sd card, or the Flash image from Sharp I mentioned in my first post.
(Yes, you can use either cf or sd to flash now!)
2. Make sure the Zaurus isn't plugged into AC power.
3. Remove battery for at least 5 seconds.
4. Replace battery (replace battery cover, lock cover), plug in AC power.
5. Press and hold the "OK" button on the keyboard.
6. Turn the power on, you should see the Japanese service menu:
7. Now Plug in the Power Cord.
(You will get an error if it isn't plugged in!)
8. Select option 3 (Erase all / Format (all data will be lost!))
9. You should then get a confirmation message (in Japanese) with a Yes/No
option (left one is Yes). Click the Yes button to confirm.
(If you don't get this, then you don't have the AC power plugged in.)
10. Wait, get some coffee/tea, watch the pretty screen.