1 the project is build android recovery only;
2 before building, make sure copy project android_prebuilt, android_bionic and anroid_hardware to the directory ,which from ICS.
3 Steps as following:
 $. build/envsetup.sh
 $make crespo
 please see the out/patch_device/crespo/ , find recovery.img 
4 please check Makefile to obtain the supported devices;