Most YT9213AJ units ship with Android security patch level dated October 5, 2017. This is ancient. A "patched" update spoofs a newer date (e.g., 2023) but also backports critical fixes for (Bluetooth takeover) and Stagefright (MMS exploits). While not a full CVE patch, it closes the most dangerous doors.
Do not just download the first file you see on a Google Drive link. Follow this checklist: yt9213aj firmware update patched