Brother HL-7050N - Manual (Page 159)

A - 6 APPENDIX
YL4US_FAX2800MFC4800-FM5.5
Reloading process
The Data LED on the printer control panel will blink during the
firmware file loading process. During programming process, the
backlight on the printer’s LCD goes off, and
Erase xxxxxx and Write
xxxxxx will be indicated alternately on the LCD. After the firmware
update is completed, the printer will re-start automatically. DO NOT
TURN OFF THE PRINTER DURING THESE PROCESSES.
If the Data LED does not stop blinking after about two minutes, check
to make sure that you correctly entered all parameters and that your
network connections are good. Then power the print server/printer
off and then on again, to retry the download.
If you encounter problems upgrading the firmware and you
find that the network portion of the printer no longer functions,
you should try re-programming the print server by using the
COPY command from the DOS prompt of your PC. To do
this, connect a parallel cable between your PC and printer
and use the command
COPY filename LPT1:/B (where
filename is the new firmware file).