I was asked by someone about the Sharp MM20’s Linux compatibility. I decided to post the info I gave him here to help anyone else thinking about getting one.
Unfortunately the Actius MM20 is a huge piece of crap. Despite it’s incredible smallness, sharp screen, long battery life and Linux compatibility (Ubuntu worked out of the box once you added a small kernel argument in grub.) The hard drive in it (at least for me) is very fragile. After I installed Linux on it and everything worked fine, I went to install Windows XP. In the middle of that install the hard drive started making noise and there was an amazing crash. I think something in the hard drive melted. This happened at the worst moment because I was going to move to Japan in less than a week.
Instead of sending it back I decided to place a rush order for a new hard drive (They are very hard to find) and replace it myself. Unfortunately the company didn’t send it using the U.S. post office so the hard drive got sent back the day before I left. Eventually I got it sent to me in Japan and replaced the hard drive. I got Ubuntu on it just fine, until I ran an update. The hard drive broke again. (This time making even worse noises.) So my theory is that the Hitachi hard drive in the MM20 is way too sensitive to use in even normal ways. Although mine was a refurbished model so it could also just as likely be a short circuit of some sort burning the hard disk.
Now my MM20 is just collecting dust in a corner of my room. I can still use it as a thin client with it’s network boot capability.