The usual stuff, Fflash at your own risk. We I am not responsible if you brick your device, burn your device, blow up your device etc. This mod might be most suitable for experienced users but everybody is welcome to try at your own risk your warranty may be void check before flashing.
1) First prepare you new memory card and get the windows flasher tool below its very easy to use
WINDOWS USERS CHOOSE ONE OF THE FOLLOWING
sd_image_frankenzero.bin is for all original 256mb GCW0 prototypes, clones, frankenzeros devices
sd_image_specialedition.bin is for all 512MB Special Edition, pre-order devices (possibly discontinued try kickstarter version if this doesn't boot)
sd_image_kickstarter.bin is for all 512MB Kickstarter, Production, or "normal" devices
if one doesn't work, yours is possibly branded incorrectly, try anotherhttps://www.dropbox.com/s/swurdbx8qo6vjr1/GCW0-Flasher-WIN-20130524.zip
(A BIG Thanks to supernesfan for the installer) & RuffNutts for his guidance.
2) Remove the 4 rubber screw plugs in the back cover and remove all 4 screws gently.
3) Use a plastic prising tool and start by the sholder triggers and gently run the tool around the gcw device until all the clips release you will feel them come away.
4) Once all release gently lift the bottom of the casing up slightly so you can see the sd card you want to replace look at the pics below so you know where to look.
5) Start by removing the static tape on the memory card and gently peel it back remove the internal card by sliding it to the right and insert the prepared card and replace the tape.
6) At all times ensuring that you do not pull the back cover up more than you need to be very gentle look at the pics and you will see the danger wires that you must be careful of.
7) Ok now you got the card in gently put the back cover back on making sure the trigger are lined up correctly and the clips will just clip in nicely.
Now replace the 4 screws ensuring you don't over tighten them like i did or you will get a white screen if this happens you have tightened the screws too tight take note.
9) Now replace the 4 rubber screw plugs in the back to cover the screw and boot your device.
10) Now you will see some repartitioning going on it will take longer for larger cards don't worry its normal eventually your device will boot open dingux.
11) If you are successful you will now see the open dingux screen and your new internal memory size will be displayed on the bottom left i suggest you update to the latest open dingux release here http://www.gcw-zero.com/updates
12) Well done you have successfully swapped out your internal card please take a look at the pictures i took while i was doing mine for illustration enjoy.https://www.dropbox.com/s/umdwuyst3a882eu/IMG_0003.JPGhttps://www.dropbox.com/s/ko208wwywck0789/IMG_0004.JPGhttps://www.dropbox.com/s/5l5u6k6ohw0ds78/IMG_0007.JPGhttps://www.dropbox.com/s/tqwnlaid1idkx8q/IMG_0008.JPGhttps://www.dropbox.com/s/645enscwiyz5gnx/IMG_0009.JPGhttps://www.dropbox.com/s/ouygl7t48org2ax/IMG_0010.JPGhttps://www.dropbox.com/s/ptq3591e5059f69/IMG_0011.JPGhttps://www.dropbox.com/s/xwa8cwf2g5ykqip/IMG_0013.JPGhttps://www.dropbox.com/s/cc1dchvz6wvg9sx/IMG_0014.JPGhttps://www.dropbox.com/s/0r70s399gpasbxt/IMG_0015.JPG