I have written this as a XDA/Forum style guide and a Reddit style summary. Choose the one that fits your platform.
adb devices
(Authorize the connection on your phone screen if prompted).adb reboot bootloader
Before diving into the "how," we must understand the "what." In an Android ecosystem, the boot.img file is a compressed partition containing two critical components: crdroid bootimg install
When you install a custom ROM like crDroid, the boot.img shipped with the ROM zip is specifically compiled for that build. Using the wrong boot image—or skipping its installation—will almost certainly lead to a bootloop or a device that never reaches the setup screen. I have written this as a XDA/Forum style
boot.img disables verified boot (dm-verity).boot.img from official crDroid sources — never from untrusted mirrors.On your phone: Settings → Developer Options → USB Debugging → Enable. Step 2: Boot to Fastboot Mode
adb reboot bootloader
Or manually: Power off → Press Volume Down + Power (varies by device).