hi

ok - did an on-device flash of the kernel :

* do a backup, have a pc nearby and know you are able to flash the n900 with flasher-3.5 - just in case
* on device :
- start "softupd -vv -s --local" within xterm as root (thats double v)
- open new terminal
- start "flasher --local -f -k <kernel_zimage_file_with_path>"
- you see the flashing - some secs
- type "sync" to be save all is stored to the discs
- type "reboot" and enter to restart

ciao and good luck

ps: the 800mhz kernel is not that much faster - than a 600mhz. i leave it anyway as it may increase battery life - i am not such a gamer - so probably the effect in overclocking is not dramatic then !