Good news for custom ROM developers, as Sony Mobile has just released the kernel source code for its recent Xperia S Android 4.0.4 update, as it's required to do under the open source rules. The open source archive, based on the just-launched v6.1.A.0.452 ICS firmware, weighs in at around 132MB, and will be an essential download for anyone preparing aftermarket firmware for Sony's international flagship phone. Regular users and ROM-flashers won't find much of interest here for the moment. Instead, the benefit of this code should show itself in the weeks ahead, in the form of stable, more functional ICS ROMs for the Xperia S.
Developers can grab the 132MB archive from Sony over at the source link.