What is custom Antminer firmware?
Antminer firmware is the software that controls how the miner starts, communicates with pools, monitors temperatures and manages performance. Custom firmware adds clearer controls for tuning, efficiency, monitoring and recovery.
The correct package depends on the exact miner model, control board and storage type. That is why the safest workflow is to identify the hardware first, download only a matching package, keep power stable during flashing and verify the miner before changing performance settings.