Also you can "Dual boot" in a fashion by using flash_image and just swapping kernels.
A couple of limitations apply, you have to setup the sdcards correctly, if you have backtrack on internal then your android rom must use the external sdcard on /sdcard.
The command to flash the kernel is:
From android:
Code:
flash_image boot linux_kernel.img
From backtrack (you must copy the flash_image binary from android or recovery):
Code:
flash_image boot your-android-kernel-image.img
Also you do not need to nvflash at all using this method as long as you are already on a 1.1 based bootlader.
In theory it would be possible to create a recovery installable .zip that would handle every part of the install of backtrack.