Press and hold down the front panel Standby button while turning the main rear power switch back to the ON position.
If you want, I can:
Features traditional analog and digital inputs, Bluetooth, and a front-panel display. It has no network streaming capabilities. Audiolab 6000a Firmware Update
Official instructions and firmware files for the Audiolab 6000A are available on the Audiolab Firmware & Drivers Press and hold down the front panel Standby
Ensure your USB flash drive is entirely empty and formatted to FAT32. Audiolab 6000a Firmware Update