Here’s a detailed content piece about “crDroid boot.img install” — explaining what it is, why you’d do it, and a step-by-step guide.
Then copy it to your PC. This is your lifeline.
Note: Some guides suggest fastboot boot boot.img (temporary). For a permanent crdroid bootimg install, you must use flash, not boot.
Backup Your Stock boot.img
Before flashing crDroid, always: