I have written this as a XDA/Forum style guide and a Reddit style summary. Choose the one that fits your platform.
Since the new boot image contains the crDroid recovery, reboot to it: crdroid bootimg install
.zip file to your PC.boot.img.platform-tools folder).If you are updating crDroid from version 9.x to 10.x, always flash the new boot.img along with the full ROM. Do not keep the old boot image. I have written this as a XDA/Forum style
Step 3: Reboot
Flash the boot image using the following command: Download the CRDroid ROM
Your device should reboot to a screen showing "Fastboot" or a similar technical menu. Step 3: Flash the crDroid boot.img
Next was vbmeta. Verity, avb — words that govern trust. Flashing vbmeta was like telling the phone it could accept a new set of rules, that signatures mattered less than possibility. I hesitated. On certain forums, people warned that altering vbmeta could void the safety net and make updates angry. I typed it anyway: fastboot --disable-verity --disable-verification flash vbmeta vbmeta.img. The command washed through the terminal and left me with a little cascade of OKAYs.