Originally Posted by titan

There is a new stable overclockable kernel in extras-testing (version 2.6.28-maemo19, not 18!!).
Installation is very simple: install the package kernel-flasher-maemo (section system in HAM), shutdown and cold boot. There's no need for reflashing etc.
It requires firmware PR1.1 or newer.

The default limit is at stable 600MHz. This is the same setting as the stock kernel and is safe.

This kernel makes it possible dynamically change the maximum frequency up to 1.2GHz (supported frequencies are 250,500,550,600,700,750,800,850,900,950,1000,1100, 1200MHz)
WARNING: Overclocking may damage your device and is at your own risk! It may void your warranty and destroy your data. You have been warned.
You can manually increase the limit until your device fries using, e.g. for 600MHz

Code:

sudo gainroot
echo 600000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq

The last line shows which value was actually set.
This setting takes effect immediately and is cleared with the next reboot or overriden by
every phone call with the value 600MHz.
To permanently fix a limit you found to be stable edit the scaling_max_freq setting in /etc/pmconfig (e.g., using vi)
and either install the new kernel http://talk.maemo.org/showpost.php?p...postcount=1765
or implement the workaround http://talk.maemo.org/showpost.php?p...postcount=1722
WARNING: Permanent overclocking is very dangerous!

Apart from overclocking, this kernel has a lot of other features
(2.6.28.10, PR1.2 SDK patches etc) see http://talk.maemo.org/showthread.php?t=43420
It also retains the version info in Settings -> Product info (if it is still available).
If it works well for you, please vote at
http://maemo.org/packages/package_in....6.28-maemo19/

For deinstallation of this kernel run

Code:

sudo gainroot
apt-get install --reinstall kernel kernel-flasher
apt-get remove kernel-maemo kernel-modules-maemo

PS: 125MHz is deliberately not included, see http://talk.maemo.org/showpost.php?p...&postcount=141

Good luck!