Hi, I had the following problem: I working in the source code of the Udoo AOSP, and I had detected that it has some kind of "cache" in the build process (I don't know the exactly name, but it works like the cache from websites). This "cache", it's really useful because it makes that after a small modification I can rebuild again the AOSP in less than 5 minutes, an avoid me to wait the 4 hours of the process just doing: Code: make bootimage or Code: make -jX The problem comes when working outside the kernel folder. I tried to add an app to the packages/apps folder and build it with it after doing the necessary modifications. I got the build successfully, but I got disappointed with the functionality of the app. Due to this I remove the app from the packages/apps and tried a new build with: Code: make -jX After the build finished, the app still there, and the problem resides in that the build is not updating the system.img file nor the files which are included on it, like system folder or installed-apps.txt file. (All this files contained in the folder out/target/product/udoo) I could execute: Code: make clean and start another build again, but this build the AOSP from the beginning (right now I am doing this) but this builds the AOSP from the beginning or nearly the beginning, I think the kernel is not compiled completely again if it was previously compiled. Is there a way of doing this task more time efficiently? Is there a way of force to update all out files without execute "make clean" ? Use 2 hours for this small change is really annoying. Any help is welcome, Spaniard.