Signature verification failed when flashing custom kernel (Siyah) I am trying to flash a custom kernel (Siyah-s2-v6.0b5-CWM) to my Samsung Galaxy S2.

When I go to recovery mode, click apply update from sdcard, and select the file, it shows this:

Finding update package...
Opening update package...
Verifying update package...
E:signature verification failed
install_package = (2)
installation aborted.


Any ideas what to do?
Is your phone still using the stock recovery? That may be the problem.

If you're trying to flash / update ClockWorkMod (CWM) zips, then you need to have CWM recovery on your phone. An easy way to install CWM would be described in this answer; needs root.