Default (and possibly architecture dependents) HAL modules go here. libhardware.so eventually should contain *just* the HAL hub (hardware.c), everything in it should be rewritten as modules. Modules are .so in /system/libs/hw/ and have a well defined naming convention: /system/libs/hw/<*_HARDWARE_MODULE_ID>..so /system/libs/hw/<*_HARDWARE_MODULE_ID>..so /system/libs/hw/<*_HARDWARE_MODULE_ID>..so /system/libs/hw/<*_HARDWARE_MODULE_ID>.default.so They also have a well defined interface which lives in include/hardware/. A module can have several variants: "default", "arch" and "board", and they're loaded in the "board", "arch" and "default" order. The source code for the "board" variant, usually lives under partners/... The source code for "default" and "arch" would usually live under hardware/modules/.