just used:

echo "echo 900000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq" | sudo gainroot

it works...so, finaly, i've back my own Overclock UI..like i had before reflash my n900. Still strange why it works before and this time it takes 4 times (x) more commands, but..just fine..it works...hardly, but..it works... thank you for all of you that help me sugesting me to try some commands and explaining me some things.

Sorry to QWERTY12, maybe not a rootsh problem ( :

Cheers to all.
Thread may be closed!

SOLVED. (Workarrounded but solved, aftar 5 days without sleep.. : \ lol :P )