Some newer devices flash recovery to the boot partition. Always check the specific installation instructions on the crDroid device page. Troubleshooting crdroid recovery.img install Issues
If this is your first time installing crDroid, go to Factory Reset > Format data/factory reset to prevent bootloops. Troubleshooting crdroid recoveryimg install
Download both the ( recovery.img ) and the crDroid ROM zip file. Some newer devices flash recovery to the boot partition
fastboot flash vbmeta vbmeta.img