"mtk-su: failed critical init step 3" is a known issue encountered when using the
Settings → About Phone → Android Security Update
The binary (and its wrapper app, MTK Easy SU ) is a tool designed to provide "temporary root" access to devices powered by MediaTek chips. It exploits a vulnerability known as CVE-2020-0069 , which allows unprivileged local users to read and write kernel memory. Unlike traditional rooting, this method is "bootless," meaning it does not modify the system or boot partitions and is lost upon a device reboot. Common Causes for Step 3 Failure
case 3: // Establish secure channel to TEE if (tee_response != ACK) return CRITICAL_FAIL;