Function keys don't work
If your F<num> keys do not work, this is probably because the kernel driver for the keyboard has defaulted to using the media keys and requiring you to use the Fn key to get to the F<num> keys. To change this behaviour, you have to change a driver setting. Do the following as root:
echo 2 > /sys/module/hid_apple/parameters/fnmode
If it tells you that the file doesn't exist, you probably have an older kernel and will have to do the following instead:
echo 2 > /sys/module/hid/parameters/pb_fnmode
Place whichever command worked for you in /etc/rc.local to make the setting permanent.
< and > have changed place with § and ½
If the < and > are switched with the § and ½ keys, run the following command:
setxkbmap -option apple:badmap
Place that command into ~/.bashrc file to have it run automatically when you log in.
You can also apply the change system-wide by creating (or editing) /etc/X11/xorg.conf.d/10-keymap.conf as such:
Section "InputClass" Identifier "keyboard catchall" MatchIsKeyboard "true" Driver "evdev" Option "XkbOptions" "apple:badmap" EndSection
If the above approach doesn't seem to work, you can add these two lines to your ~/.Xmodmap file:
keycode 49 = less greater less greater bar brokenbar keycode 94 = section degree section degree notsign notsign
If you use a Canadian multilingual layout (where the "ù" and the "/" is switch) use this :
keycode 94 = slash backslash slash backslash bar brokenbar keycode 49 = ugrave Ugrave ugrave Ugrave notsign notsign
Then run xmodmap ~/.Xmodmap. This command can also go into ~/.bashrc.
The evdev driver should produce keycodes that map to the appropriate keysyms for your media keys by default. You can confirm that by running xev in a console window and watching the console output as you press your media keys.
For these keys to have any effect, you will have to assign actions to them. Refer to Extra Keyboard Keys in Xorg for more about that.
If you have confirmed that your media keys are not producing the correct keycodes, create or edit the ~/.Xmodmap file so that it includes these lines:
keycode 160 = XF86AudioMute keycode 176 = XF86AudioRaiseVolume keycode 174 = XF86AudioLowerVolume keycode 144 = XF86AudioPrev keycode 162 = XF86AudioPlay keycode 153 = XF86AudioNext keycode 101 = XF86MonBrightnessDown keycode 212 = XF86MonBrightnessUp keycode 204 = XF86Eject
and then run xmodmap ~/.Xmodmap. Place that command in the ~/.bashrc file to have it run automatically when you log in.