UPDATES:
Solved the upgrade issue. I do have a SG300-20 with release 1.1.2.0.
First is to downgrade to Boot 1.3.5.06 (via TFT) and Image 1.3.5.5.58
Second upgrade to Image 1.4.1.3
Third upgrade to Image 1.4.9.4
End
I did followed your steps, I succ...