Anyone's help would be much appreciated!

I've been installing stuff like mad onto my n810 (I've cloned the OS onto an 8 GB (micro to mini) SD card so I've plenty of room for now).
I recently noticed that the Fn key no longer is working on my SD card installation--when I press Fn, nothing happens. Now, I have to use the on-screen keyboard to enter punctuation and numbers. When I boot onto the version of Diablo in the internal flash memory, the Fn key works fine.
I suspect that this problem is due to something I installed recently, but I'm not sure what. I recently installed updates to scummvm games and mclock. I also installed maemo-pc-connectivity and bluemaemo 0.2 (although the latter won't update now for some reason). I also have a strange thing: an OS2008 Feature Upgrade shows up in my upgrade alert/Application Mgr. When I tried to upgrade, it told me that I was missing these files:

kernel-diablo-flasher
xserver-xomap

I could not find these easily in the gronmayer repositories or by putting the Application Mgr into Red Pill mode. I tried downloading xserver-xomap as part of the package for the slideout-rotate app, but that didn't affect the problems with downloading the Feature Upgrade. Curiously, my internal memory version of Diablo shows no need for this upgrade even though it was the original source for the clone on the SD card.

The main problem: can anyone tell me how I might reactivate my Fn key? I'm thinking that I might need to reflash my OS all over again and start at the beginning (now that I've played around with this for my first few weeks in Maemo). Thanks! These forums are great!

Please see the existing "Lost Fn key functions" thread for a possible solution.

Sounds like the same symptoms I had a while ago. In my case, I was trying to get VNC server to accept mouse clicks properly. I read on the net that the problem was caused by an X-Windows input extension which allowed the tablet to detect pressure on the screen and differentiate finger taps from stylus taps.

The suggestion was to disable that extension, so I tried it. The side effects are exactly like what you're describing. The Fn key stopped working, as did the Chr key. I assume the same input extension handles those as well. It might have been a viable suggestion on an n770 or n800, but it's no good at all on a tablet with a physical keyboard.

You can check for this by looking at /etc/init.d/x-server. There's a line near the top that lists the arguments given to the server at startup. If that line contains "-extension XInputExtension", then the extension is disabled. You should be able to remove that part of the line and reboot.

For the record, the x-server args on my n810 are:

As far as I know, this is the standard configuration.

Thanks!
I was able to restore Fn function! I followed the instructions from your posts (and from the referenced posts) and now the Fn key works.

What I did:
1. Started xterm
2. Gained root access: "sudo gainroot"
3. Started emelFM2 from xterm: "emelfm2"
4. Looked for "/etc/init.d/x-server" in emelFM2
5. Highlighted the x-server file in emelFM2
6. Hit the "edit" button in emelFM2 (the one with a paper and pencil icon)
7. Found the offending line near the top of x-server:
ARGS="-mouse tslib -nozap -dpi $DISPLAY_DPI -wr -nolisten tcp -extension XInputExtension"
8. removed "-extension XinputExtension" with the backspace key to leave the correct argument:
ARGS="-mouse tslib -nozap -dpi $DISPLAY_DPI -wr -nolisten tcp"
9. Hit the "Save" button, then "Close" button.
10. Exited all apps and then rebooted
11. Tested the Fn key and it worked!

Thank you all! It looks like I can put off wiping my SD card installation for another day!