Your device may be bootloader-locked permanently. Check XDA’s TB8505F forum for exploit-based tools (e.g., MTK Client, SP Flash Tool exploits). These are advanced and risky.
Rooting can brick your device or void your warranty. Proceed at your own risk. 1. Preparation & Unlocking Bootloader
Copy this patched image file back to your PC. Step 3: Flash and Root
: Run fastboot reboot . The tablet will now wipe and restart. Step 2: Patch the Boot Image
: Go to Settings > System > Developer Options and toggle on: OEM Unlocking USB Debugging