no, see https://bugs.maemo.org/show_bug.cgi?id=965
feel free to vote for it

My workaround is modified kernel http://fanoush.wz.cz/maemo/#backlight , bootmenu and then setting low brightness early in bootmenu.conf. But still the display is bright few seconds early in boot until linux kernel boots an runs this code. To fix it we would need to hack bootloader which is a bit risky (i.e. there is quite high chance to produce nice paperweight).