Recently I’ve updated my recovery image for N1 from 1.6.2 to 1.7.0. Here’s how to do it in terminal (I like to use terminal btw🙂 ) :
– Copy recovery-RA-nexus-v1.7.0.img to the root of your sdcard
– Start the terminal app
$ su # flash_image recovery /sdcard/recovery-RA-nexus-v1.7.0.img # reboot recovery
Credit to Amon_RA from XDA.