Because it removes safety checks, you can flash the wrong firmware to the wrong partition, which may result in a permanent "hard brick" (a dead phone). Complex Setup:
Official LGUP refuses to flash firmware meant for a different model number (e.g., flashing a LM-V600TM firmware onto a LM-V600EA). The patched version removes this barrier. lgup 1.17 patched
The command line will display a progress percentage, advancing from 1% to 4%, and eventually to 100%. The phone will automatically reboot once the flashing is complete. Because it removes safety checks, you can flash