Mark I/II:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_Quantum_5p01.zip
XL:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_xl_Quantum_5p01.zip
XL+:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_xlplus_Quantum_5p01.zip
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_Quantum_5p01.zip
XL:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_xl_Quantum_5p01.zip
XL+:
www.fractalaudio.com/downloads/firmware-presets/axe-fx-2/Quantum/5.0/axefx2_xlplus_Quantum_5p01.zip