Try a different USB cable or port. Use a USB 2.0 port if possible.
: Usually a .exe script for Windows PCs or a .sh shell script for Linux/Mac environments.
: Use a high-quality USB-C to USB-A cable and a reliable Windows or Mac computer. Avoid using USB hubs.
: Some users report that after using certain autoloaders, the phone may lose its "safe environment" status, causing issues with apps like Google Pay. Others have noted difficulty passing the initial Google Play connection screen after a fresh reload.
There is one absolute rule for the BlackBerry KEYone that cannot be overstated:
Press and hold the button and the Power button simultaneously.
An autoloader is a specialized installation file that contains the entire factory operating system for your device. Unlike standard "Over the Air" (OTA) updates, an autoloader: Wipes Everything
(Windows users) or execute sh flashall.sh via the Terminal (Mac/Linux users).
You plug in your KeyOne. The notification LED blinks red three times. The screen stays black. The device is unrecognized by Windows Device Manager as anything other than "Qualcomm HS-USB QDLoader 9008." This is a hard brick. The Autoloader (using Emergency Download mode) is the only fix.