There are a couple ways you can upgrade:
1. Wire Backlight ON
As you noted, you can wire the backlight so it's always on. Most backlights work if you just leave the on/off pin floating. If you can reach the backlight cable, it's just a matter of carefully pulling one pin out of the connector.
2. Command prompt on serial port
If you can't do that easily, you also can update the ADSmartIO using the CE command prompt on one of the serial ports. Here are details:
a. Change your ADSLOAD.REG file to put the command prompt on one of your serial ports (see this topic for details).
b. If you have two serial ports, use one to monitor the debug port for status codes.
c. Put cmd.exe in the Startup folder of a PC Card and boot your system.
You should see the CE command
d. Type the following commands at the prompt (under the cmd prompt, file names in quotes are case-sensitive):
copy "Storage Card\SMARTIO.BIN" \
avrprog
Note that the backlight may go off during reprogramming.