A flashing cursor during Kali Linux installation usually indicates a problem with the graphics drivers or boot process. To troubleshoot, try switching to a different TTY (terminal) using Ctrl + Alt + F2 (or F1-F6) and logging in. If that works, you can try updating the system, checking the /etc/network/interfaces file, or booting into recovery mode. If the issue persists, consider reinstalling or trying a different bootable USB creation tool.