Dell 2130cn Service Manual page 82

Reference_2:
1. Make sure that the printer is connected to the computer via USB port (remove the network cable).
Then, try downloading as follows:
1) Power on the printer while pressing the <X Cancel> and < > buttons.
2) The printer goes into the Download Mode with a message "Download Mode Ready". Then,
activate firmware update tool and follow the instruction displayed.
While the firmware download is being executed, the printer displays a message
"Writing...USB F/W" and the computer displays a progress bar and may be
restarted during the downloading process. Never power off the printer or the
computer until the downloading process completes, and never interrupt the
downloading process.
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Chapter 1 Troubleshooting