This means the ROM zip file detected a model mismatch. Ensure you downloaded a ROM explicitly configured for the BG2-U01. You can also fix this by editing the updater-script inside the ROM zip file to remove the device assert checks.

If your 3G connectivity stops working after flashing, your NVRAM partition may have been corrupted. You will need to restore an NVRAM backup or rewrite your IMEI using MTK specialized tools. Finding Reliable ROM Files

Download the compatible TWRP recovery image ( .img ) specifically compiled for the BG2-U01 model. Boot your tablet back into Fastboot mode.

Installed and configured on your PC. 3. Critical Preparations