By Hans Boehling
An extract from the full article on Hans Boehling's website

How to open the NC100

Before dis-assembling the Notepad you should save all your data! Then put your Notepad on the table face down. Remove the four AA batteries (if fitted), then unscrew the five screws (one under the battery cover).
In Figure 1 below they are marked with a '*' sign.

One screw fixes the cover of the firmware