User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:184.108.40.206) Gecko/20090729 Firefox/3.5.2 Build Identifier: The installer will execute "fennec.exe -silent" at the last stage of installation to create user's profile. Splash screen should not be shown in this case. Reproducible: Always
Seems like this bug is not very important at the moment as adding also "-nosplash" parameter does what is needed. It probably still makes sense to make it properly "silent" though.
This year we mothballed windows mobile development. See: http://blog.pavlov.net/2010/03/22/stopping-development-for-windows-mobile/ Marking bugs in the windows mobile / windows ce bucket as WONTFIX.