I think I’ve got it down but not in a form that I could recommend anyone else using. Ever. Here are the steps that seem to work after massive googlage.
1. Update original (non-alias) icon as desired.
2. Delete aliases (Yes doctor, kill the patient)
3. Trash cache.
sudo /usr/bin/find /private/var/folders/ -name com.apple.dock.iconcache -exec rm {} \;
sudo /usr/bin/find /private/var/folders/ -name com.apple.iconservices -exec rm -rf {} \;
cd /Library/Caches/; sudo rm -rf com.apple.iconservices.store
4. Log out and back in or reboot computer. (No, really.)
5. Recreate the aliases or symbolic links.
For anyone who wants a good laugh, search the web for OS X alias icons won’t update.
One Comment
Weird… I followed your steps and instead of logging out, I tried stuff like “sudo launchctl unload /System/Library/LaunchDaemons/com.apple.iconservices.iconservicesd.plist” and relaunching Finder, but neither refreshed the icons.