Question [Q] callbacks not invoked in Kitkat


I am developing a module for which I have hooked callback. The code is like this -
Unhook hook = findAndHookMethod(,
		    		new XC_MethodHook() {
	            protected void afterHookedMethod(MethodHookParam param) throws Throwable {
	            	log("After enqueue.");
This code is invoked from initZygote. It was working perfectly fine in Jellybean 4.1.2 on my older Xperia J. However, the callback is not invoked in Xperia Z running Kitkat 4.4.2 ROM. The callback does get attached successfully since the "hook" value is not null. I have tried moving the invoke into handlePackageLoad when the "android" package is loaded, but still no luck.

Any suggestions?