Hello, I did several tests and got the solution.
I used a Kingston pendrive it worked out, probably the printer will not some pendrive.
I had some incompatibility with fw but I tested all I could and what worked was the (mamba-system-spar-sw-sw # 07116022310700 #) I created a folder called AltBoot on the pendrive and put the FW and la plus the file FORCED_UPGRADE and it worked .. I hope they help you.
Hugs